diff --git a/README.md b/README.md
index 9d699a2..624b74b 100644
--- a/README.md
+++ b/README.md
@@ -148,7 +148,7 @@ iterations of Miller-Rabin Probabilistic Primality Test (FIPS 186-4 C.3.1)</p>
 <dt><a href="#min">min(a, b)</a> ⇒ <code>bigint</code></dt>
 <dd><p>Minimum. min(a,b)==b if a&gt;=b. min(a,b)==a if a&lt;=b</p>
 </dd>
-<dt><a href="#modInv">modInv(a, n)</a> ⇒ <code>bigint</code> | <code>NaN</code></dt>
+<dt><a href="#modInv">modInv(a, n)</a> ⇒ <code>bigint</code></dt>
 <dd><p>Modular inverse.</p>
 </dd>
 <dt><a href="#modPow">modPow(b, e, n)</a> ⇒ <code>bigint</code></dt>
@@ -225,6 +225,10 @@ Take positive integers a, b as input, and return a triple (g, x, y), such that a
 
 **Kind**: global function  
 **Returns**: [<code>egcdReturn</code>](#egcdReturn) - A triple (g, x, y), such that ax + by = g = gcd(a, b).  
+**Throws**:
+
+- <code>RangeError</code> a and b MUST be > 0
+
 
 | Param | Type |
 | --- | --- |
@@ -318,11 +322,15 @@ Minimum. min(a,b)==b if a>=b. min(a,b)==a if a<=b
 
 <a name="modInv"></a>
 
-### modInv(a, n) ⇒ <code>bigint</code> \| <code>NaN</code>
+### modInv(a, n) ⇒ <code>bigint</code>
 Modular inverse.
 
 **Kind**: global function  
-**Returns**: <code>bigint</code> \| <code>NaN</code> - the inverse modulo n or NaN if it does not exist  
+**Returns**: <code>bigint</code> - the inverse modulo n  
+**Throws**:
+
+- <code>RangeError</code> a does not have inverse modulo n
+
 
 | Param | Type | Description |
 | --- | --- | --- |
diff --git a/lib/index.browser.bundle.iife.js b/lib/index.browser.bundle.iife.js
index 73d1906..8e0820b 100644
--- a/lib/index.browser.bundle.iife.js
+++ b/lib/index.browser.bundle.iife.js
@@ -1 +1 @@
-var bigintCryptoUtils=function(n){"use strict";function t(n){return(n=BigInt(n))>=0n?n:-n}function e(n){if(1n===(n=BigInt(n)))return 1;let t=1;do{t++}while((n>>=1n)>1n);return t}function r(n,t){if((n=BigInt(n))<=0n|(t=BigInt(t))<=0n)throw new RangeError("a and b MUST be > 0");let e=0n,r=1n,o=1n,i=0n;for(;0n!==n;){const s=t/n,a=t%n,c=e-o*s,u=r-i*s;t=n,n=a,e=o,r=i,o=c,i=u}return{g:t,x:e,y:r}}function o(n,e){if(n=t(n),e=t(e),0n===n)return e;if(0n===e)return n;let r=0n;for(;!(1n&(n|e));)n>>=1n,e>>=1n,r++;for(;!(1n&n);)n>>=1n;do{for(;!(1n&e);)e>>=1n;if(n>e){const t=n;n=e,e=t}e-=n}while(e);return n<<r}function i(n,t){try{const e=r(a(n,t),t);return 1n!==e.g?NaN:a(e.x,t)}catch(n){return NaN}}function s(n,e,r){if(0n===(r=BigInt(r)))return NaN;if(1n===r)return BigInt(0);if(n=a(n,r),(e=BigInt(e))<0n)return i(s(n,t(e),r),r);let o=1n;for(;e>0;)e%2n===1n&&(o=o*n%r),e/=2n,n=n**2n%r;return o}function a(n,t){return(t=BigInt(t))<=0?NaN:(n=BigInt(n)%t)<0?n+t:n}function c(n,t=16,e=!1){if("number"==typeof n&&(n=BigInt(n)),n<0)throw RangeError("w MUST be >= 0");return new Promise((e,r)=>{const o=new Worker(d());o.onmessage=n=>{o.terminate(),e(n.data.isPrime)},o.onmessageerror=n=>{r(n)},o.postMessage({rnd:n,iterations:t,id:0})})}function u(n,t=1n){if(n<=0n||t<0n||n<=t)throw new RangeError("Arguments MUST be: max > 0 && min >=0 && max > min");const r=n-t,o=e(r);let i;do{i=m(g(o))}while(i>r);return i+t}function f(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=Math.ceil(n/8),r=n%8;return new Promise(n=>{l(e,!1).then((function(e){if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}n(e)}))})}function g(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=w(Math.ceil(n/8),!1),r=n%8;if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}return e}function l(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");return new Promise((function(e,r){{const r=new Uint8Array(n);self.crypto.getRandomValues(r),t&&(r[0]=128|r[0]),e(r)}}))}function w(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");{const e=new Uint8Array(n);return self.crypto.getRandomValues(e),t&&(e[0]=128|e[0]),e}}function m(n){let t=0n;for(const e of n.values()){const n=BigInt(e);t=(t<<BigInt(8))+n}return t}function d(){let n=`'use strict';const ${r.name}=${r.toString()};const ${i.name}=${i.toString()};const ${s.name}=${s.toString()};const ${a.name}=${a.toString()};const ${g.name}=${g.toString()};const ${w.name}=${w.toString()};const ${u.name}=${u.toString()};const ${c.name}=${h.toString()};${e.toString()}${m.toString()}`;return n+=`onmessage = ${async function(n){const t=await c(n.data.rnd,n.data.iterations);postMessage({isPrime:t,value:n.data.rnd,id:n.data.id})}.toString()};`,function(n){n=`(() => {${n}})()`;const t=new Blob([n],{type:"text/javascript"});return window.URL.createObjectURL(t)}(n)}function h(n,t=16){if(2n===n)return!0;if(0n===(1n&n)||1n===n)return!1;const e=[3n,5n,7n,11n,13n,17n,19n,23n,29n,31n,37n,41n,43n,47n,53n,59n,61n,67n,71n,73n,79n,83n,89n,97n,101n,103n,107n,109n,113n,127n,131n,137n,139n,149n,151n,157n,163n,167n,173n,179n,181n,191n,193n,197n,199n,211n,223n,227n,229n,233n,239n,241n,251n,257n,263n,269n,271n,277n,281n,283n,293n,307n,311n,313n,317n,331n,337n,347n,349n,353n,359n,367n,373n,379n,383n,389n,397n,401n,409n,419n,421n,431n,433n,439n,443n,449n,457n,461n,463n,467n,479n,487n,491n,499n,503n,509n,521n,523n,541n,547n,557n,563n,569n,571n,577n,587n,593n,599n,601n,607n,613n,617n,619n,631n,641n,643n,647n,653n,659n,661n,673n,677n,683n,691n,701n,709n,719n,727n,733n,739n,743n,751n,757n,761n,769n,773n,787n,797n,809n,811n,821n,823n,827n,829n,839n,853n,857n,859n,863n,877n,881n,883n,887n,907n,911n,919n,929n,937n,941n,947n,953n,967n,971n,977n,983n,991n,997n,1009n,1013n,1019n,1021n,1031n,1033n,1039n,1049n,1051n,1061n,1063n,1069n,1087n,1091n,1093n,1097n,1103n,1109n,1117n,1123n,1129n,1151n,1153n,1163n,1171n,1181n,1187n,1193n,1201n,1213n,1217n,1223n,1229n,1231n,1237n,1249n,1259n,1277n,1279n,1283n,1289n,1291n,1297n,1301n,1303n,1307n,1319n,1321n,1327n,1361n,1367n,1373n,1381n,1399n,1409n,1423n,1427n,1429n,1433n,1439n,1447n,1451n,1453n,1459n,1471n,1481n,1483n,1487n,1489n,1493n,1499n,1511n,1523n,1531n,1543n,1549n,1553n,1559n,1567n,1571n,1579n,1583n,1597n];for(let t=0;t<e.length&&e[t]<=n;t++){const r=e[t];if(n===r)return!0;if(n%r===0n)return!1}let r=0n;const o=n-1n;let i=o;for(;i%2n===0n;)i/=2n,++r;const a=o/2n**r;do{let t=s(u(o,2n),a,n);if(1n===t||t===o)continue;let e=1;for(;e<r&&(t=s(t,2n,n),t!==o);){if(1n===t)return!1;e++}if(t!==o)return!1}while(--t);return!0}let B=!1;return self.Worker&&(B=!0),n.abs=t,n.bitLength=e,n.eGcd=r,n.gcd=o,n.isProbablyPrime=c,n.lcm=function(n,e){return n=BigInt(n),e=BigInt(e),0n===n&&0n===e?BigInt(0):t(n*e)/o(n,e)},n.max=function(n,t){return(n=BigInt(n))>=(t=BigInt(t))?n:t},n.min=function(n,t){return(n=BigInt(n))>=(t=BigInt(t))?t:n},n.modInv=i,n.modPow=s,n.prime=function(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");if(!B){let e=0n;do{e=m(g(n,!0))}while(!h(e,t));return new Promise(n=>{n(e)})}return new Promise(e=>{const r=[],o=(o,i)=>{if(o.isPrime){for(let n=0;n<r.length;n++)r[n].terminate();for(;r.length;)r.pop();e(o.value)}else{const e=m(g(n,!0));try{i.postMessage({rnd:e,iterations:t,id:o.id})}catch(n){}}};{const n=d();for(let t=0;t<self.navigator.hardwareConcurrency-1;t++){const t=new Worker(n);t.onmessage=n=>o(n.data,t),r.push(t)}}for(let e=0;e<r.length;e++)f(n,!0).then((function(n){const o=m(n);r[e].postMessage({rnd:o,iterations:t,id:e})}))})},n.primeSync=function(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");let e=0n;do{e=m(g(n,!0))}while(!h(e,t));return e},n.randBetween=u,n.randBits=f,n.randBitsSync=g,n.randBytes=l,n.randBytesSync=w,n.toZn=a,n}({});
+var bigintCryptoUtils=function(n){"use strict";function t(n){return(n=BigInt(n))>=0n?n:-n}function e(n){if(1n===(n=BigInt(n)))return 1;let t=1;do{t++}while((n>>=1n)>1n);return t}function r(n,t){if((n=BigInt(n))<=0n|(t=BigInt(t))<=0n)throw new RangeError("a and b MUST be > 0");let e=0n,r=1n,o=1n,i=0n;for(;0n!==n;){const s=t/n,a=t%n,c=e-o*s,u=r-i*s;t=n,n=a,e=o,r=i,o=c,i=u}return{g:t,x:e,y:r}}function o(n,e){if(n=t(n),e=t(e),0n===n)return e;if(0n===e)return n;let r=0n;for(;!(1n&(n|e));)n>>=1n,e>>=1n,r++;for(;!(1n&n);)n>>=1n;do{for(;!(1n&e);)e>>=1n;if(n>e){const t=n;n=e,e=t}e-=n}while(e);return n<<r}function i(n,t){const e=r(a(n,t),t);if(1n!==e.g)throw new RangeError(`${n.toString()} does not have inverse modulo ${t.toString()}`);return a(e.x,t)}function s(n,e,r){if(0n===(r=BigInt(r)))throw new RangeError("n must be > 0");if(1n===r)return BigInt(0);if(n=a(n,r),(e=BigInt(e))<0n)return i(s(n,t(e),r),r);let o=1n;for(;e>0;)e%2n===1n&&(o=o*n%r),e/=2n,n=n**2n%r;return o}function a(n,t){return(t=BigInt(t))<=0?NaN:(n=BigInt(n)%t)<0?n+t:n}function c(n,t=16,e=!1){if("number"==typeof n&&(n=BigInt(n)),n<0)throw RangeError("w MUST be >= 0");return new Promise((e,r)=>{const o=new Worker(d());o.onmessage=n=>{o.terminate(),e(n.data.isPrime)},o.onmessageerror=n=>{r(n)},o.postMessage({rnd:n,iterations:t,id:0})})}function u(n,t=1n){if(n<=0n||t<0n||n<=t)throw new RangeError("Arguments MUST be: max > 0 && min >=0 && max > min");const r=n-t,o=e(r);let i;do{i=m(g(o))}while(i>r);return i+t}function f(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=Math.ceil(n/8),r=n%8;return new Promise(n=>{l(e,!1).then((function(e){if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}n(e)}))})}function g(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=w(Math.ceil(n/8),!1),r=n%8;if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}return e}function l(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");return new Promise((function(e,r){{const r=new Uint8Array(n);self.crypto.getRandomValues(r),t&&(r[0]=128|r[0]),e(r)}}))}function w(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");{const e=new Uint8Array(n);return self.crypto.getRandomValues(e),t&&(e[0]=128|e[0]),e}}function m(n){let t=0n;for(const e of n.values()){const n=BigInt(e);t=(t<<BigInt(8))+n}return t}function d(){let n=`'use strict';const ${r.name}=${r.toString()};const ${i.name}=${i.toString()};const ${s.name}=${s.toString()};const ${a.name}=${a.toString()};const ${g.name}=${g.toString()};const ${w.name}=${w.toString()};const ${u.name}=${u.toString()};const ${c.name}=${h.toString()};${e.toString()}${m.toString()}`;return n+=`onmessage = ${async function(n){const t=await c(n.data.rnd,n.data.iterations);postMessage({isPrime:t,value:n.data.rnd,id:n.data.id})}.toString()};`,function(n){n=`(() => {${n}})()`;const t=new Blob([n],{type:"text/javascript"});return window.URL.createObjectURL(t)}(n)}function h(n,t=16){if(2n===n)return!0;if(0n===(1n&n)||1n===n)return!1;const e=[3n,5n,7n,11n,13n,17n,19n,23n,29n,31n,37n,41n,43n,47n,53n,59n,61n,67n,71n,73n,79n,83n,89n,97n,101n,103n,107n,109n,113n,127n,131n,137n,139n,149n,151n,157n,163n,167n,173n,179n,181n,191n,193n,197n,199n,211n,223n,227n,229n,233n,239n,241n,251n,257n,263n,269n,271n,277n,281n,283n,293n,307n,311n,313n,317n,331n,337n,347n,349n,353n,359n,367n,373n,379n,383n,389n,397n,401n,409n,419n,421n,431n,433n,439n,443n,449n,457n,461n,463n,467n,479n,487n,491n,499n,503n,509n,521n,523n,541n,547n,557n,563n,569n,571n,577n,587n,593n,599n,601n,607n,613n,617n,619n,631n,641n,643n,647n,653n,659n,661n,673n,677n,683n,691n,701n,709n,719n,727n,733n,739n,743n,751n,757n,761n,769n,773n,787n,797n,809n,811n,821n,823n,827n,829n,839n,853n,857n,859n,863n,877n,881n,883n,887n,907n,911n,919n,929n,937n,941n,947n,953n,967n,971n,977n,983n,991n,997n,1009n,1013n,1019n,1021n,1031n,1033n,1039n,1049n,1051n,1061n,1063n,1069n,1087n,1091n,1093n,1097n,1103n,1109n,1117n,1123n,1129n,1151n,1153n,1163n,1171n,1181n,1187n,1193n,1201n,1213n,1217n,1223n,1229n,1231n,1237n,1249n,1259n,1277n,1279n,1283n,1289n,1291n,1297n,1301n,1303n,1307n,1319n,1321n,1327n,1361n,1367n,1373n,1381n,1399n,1409n,1423n,1427n,1429n,1433n,1439n,1447n,1451n,1453n,1459n,1471n,1481n,1483n,1487n,1489n,1493n,1499n,1511n,1523n,1531n,1543n,1549n,1553n,1559n,1567n,1571n,1579n,1583n,1597n];for(let t=0;t<e.length&&e[t]<=n;t++){const r=e[t];if(n===r)return!0;if(n%r===0n)return!1}let r=0n;const o=n-1n;let i=o;for(;i%2n===0n;)i/=2n,++r;const a=o/2n**r;do{let t=s(u(o,2n),a,n);if(1n===t||t===o)continue;let e=1;for(;e<r&&(t=s(t,2n,n),t!==o);){if(1n===t)return!1;e++}if(t!==o)return!1}while(--t);return!0}let b=!1;return self.Worker&&(b=!0),n.abs=t,n.bitLength=e,n.eGcd=r,n.gcd=o,n.isProbablyPrime=c,n.lcm=function(n,e){return n=BigInt(n),e=BigInt(e),0n===n&&0n===e?BigInt(0):t(n*e)/o(n,e)},n.max=function(n,t){return(n=BigInt(n))>=(t=BigInt(t))?n:t},n.min=function(n,t){return(n=BigInt(n))>=(t=BigInt(t))?t:n},n.modInv=i,n.modPow=s,n.prime=function(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");if(!b){let e=0n;do{e=m(g(n,!0))}while(!h(e,t));return new Promise(n=>{n(e)})}return new Promise(e=>{const r=[],o=(o,i)=>{if(o.isPrime){for(let n=0;n<r.length;n++)r[n].terminate();for(;r.length;)r.pop();e(o.value)}else{const e=m(g(n,!0));try{i.postMessage({rnd:e,iterations:t,id:o.id})}catch(n){}}};{const n=d();for(let t=0;t<self.navigator.hardwareConcurrency-1;t++){const t=new Worker(n);t.onmessage=n=>o(n.data,t),r.push(t)}}for(let e=0;e<r.length;e++)f(n,!0).then((function(n){const o=m(n);r[e].postMessage({rnd:o,iterations:t,id:e})}))})},n.primeSync=function(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");let e=0n;do{e=m(g(n,!0))}while(!h(e,t));return e},n.randBetween=u,n.randBits=f,n.randBitsSync=g,n.randBytes=l,n.randBytesSync=w,n.toZn=a,n}({});
diff --git a/lib/index.browser.bundle.mod.js b/lib/index.browser.bundle.mod.js
index 5079fc9..4f802f3 100644
--- a/lib/index.browser.bundle.mod.js
+++ b/lib/index.browser.bundle.mod.js
@@ -1 +1 @@
-function n(n){return(n=BigInt(n))>=0n?n:-n}function t(n){if(1n===(n=BigInt(n)))return 1;let t=1;do{t++}while((n>>=1n)>1n);return t}function e(n,t){if((n=BigInt(n))<=0n|(t=BigInt(t))<=0n)throw new RangeError("a and b MUST be > 0");let e=0n,r=1n,o=1n,i=0n;for(;0n!==n;){const s=t/n,a=t%n,c=e-o*s,u=r-i*s;t=n,n=a,e=o,r=i,o=c,i=u}return{g:t,x:e,y:r}}function r(t,e){if(t=n(t),e=n(e),0n===t)return e;if(0n===e)return t;let r=0n;for(;!(1n&(t|e));)t>>=1n,e>>=1n,r++;for(;!(1n&t);)t>>=1n;do{for(;!(1n&e);)e>>=1n;if(t>e){const n=t;t=e,e=n}e-=t}while(e);return t<<r}function o(t,e){return t=BigInt(t),e=BigInt(e),0n===t&&0n===e?BigInt(0):n(t*e)/r(t,e)}function i(n,t){return(n=BigInt(n))>=(t=BigInt(t))?n:t}function s(n,t){return(n=BigInt(n))>=(t=BigInt(t))?t:n}function a(n,t){try{const r=e(u(n,t),t);return 1n!==r.g?NaN:u(r.x,t)}catch(n){return NaN}}function c(t,e,r){if(0n===(r=BigInt(r)))return NaN;if(1n===r)return BigInt(0);if(t=u(t,r),(e=BigInt(e))<0n)return a(c(t,n(e),r),r);let o=1n;for(;e>0;)e%2n===1n&&(o=o*t%r),e/=2n,t=t**2n%r;return o}function u(n,t){return(t=BigInt(t))<=0?NaN:(n=BigInt(n)%t)<0?n+t:n}function f(n,t=16,e=!1){if("number"==typeof n&&(n=BigInt(n)),n<0)throw RangeError("w MUST be >= 0");return new Promise((e,r)=>{const o=new Worker($());o.onmessage=n=>{o.terminate(),e(n.data.isPrime)},o.onmessageerror=n=>{r(n)},o.postMessage({rnd:n,iterations:t,id:0})})}function g(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");if(!I){let e=0n;do{e=S(m(n,!0))}while(!b(e,t));return new Promise(n=>{n(e)})}return new Promise(e=>{const r=[],o=(o,i)=>{if(o.isPrime){for(let n=0;n<r.length;n++)r[n].terminate();for(;r.length;)r.pop();e(o.value)}else{const e=S(m(n,!0));try{i.postMessage({rnd:e,iterations:t,id:o.id})}catch(n){}}};{const n=$();for(let t=0;t<self.navigator.hardwareConcurrency-1;t++){const t=new Worker(n);t.onmessage=n=>o(n.data,t),r.push(t)}}for(let e=0;e<r.length;e++)h(n,!0).then((function(n){const o=S(n);r[e].postMessage({rnd:o,iterations:t,id:e})}))})}function l(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");let e=0n;do{e=S(m(n,!0))}while(!b(e,t));return e}function w(n,e=1n){if(n<=0n||e<0n||n<=e)throw new RangeError("Arguments MUST be: max > 0 && min >=0 && max > min");const r=n-e,o=t(r);let i;do{i=S(m(o))}while(i>r);return i+e}function h(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=Math.ceil(n/8),r=n%8;return new Promise(n=>{d(e,!1).then((function(e){if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}n(e)}))})}function m(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=B(Math.ceil(n/8),!1),r=n%8;if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}return e}function d(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");return new Promise((function(e,r){{const r=new Uint8Array(n);self.crypto.getRandomValues(r),t&&(r[0]=128|r[0]),e(r)}}))}function B(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");{const e=new Uint8Array(n);return self.crypto.getRandomValues(e),t&&(e[0]=128|e[0]),e}}function S(n){let t=0n;for(const e of n.values()){const n=BigInt(e);t=(t<<BigInt(8))+n}return t}function $(){let n=`'use strict';const ${e.name}=${e.toString()};const ${a.name}=${a.toString()};const ${c.name}=${c.toString()};const ${u.name}=${u.toString()};const ${m.name}=${m.toString()};const ${B.name}=${B.toString()};const ${w.name}=${w.toString()};const ${f.name}=${b.toString()};${t.toString()}${S.toString()}`;return n+=`onmessage = ${async function(n){const t=await f(n.data.rnd,n.data.iterations);postMessage({isPrime:t,value:n.data.rnd,id:n.data.id})}.toString()};`,function(n){n=`(() => {${n}})()`;const t=new Blob([n],{type:"text/javascript"});return window.URL.createObjectURL(t)}(n)}function b(n,t=16){if(2n===n)return!0;if(0n===(1n&n)||1n===n)return!1;const e=[3n,5n,7n,11n,13n,17n,19n,23n,29n,31n,37n,41n,43n,47n,53n,59n,61n,67n,71n,73n,79n,83n,89n,97n,101n,103n,107n,109n,113n,127n,131n,137n,139n,149n,151n,157n,163n,167n,173n,179n,181n,191n,193n,197n,199n,211n,223n,227n,229n,233n,239n,241n,251n,257n,263n,269n,271n,277n,281n,283n,293n,307n,311n,313n,317n,331n,337n,347n,349n,353n,359n,367n,373n,379n,383n,389n,397n,401n,409n,419n,421n,431n,433n,439n,443n,449n,457n,461n,463n,467n,479n,487n,491n,499n,503n,509n,521n,523n,541n,547n,557n,563n,569n,571n,577n,587n,593n,599n,601n,607n,613n,617n,619n,631n,641n,643n,647n,653n,659n,661n,673n,677n,683n,691n,701n,709n,719n,727n,733n,739n,743n,751n,757n,761n,769n,773n,787n,797n,809n,811n,821n,823n,827n,829n,839n,853n,857n,859n,863n,877n,881n,883n,887n,907n,911n,919n,929n,937n,941n,947n,953n,967n,971n,977n,983n,991n,997n,1009n,1013n,1019n,1021n,1031n,1033n,1039n,1049n,1051n,1061n,1063n,1069n,1087n,1091n,1093n,1097n,1103n,1109n,1117n,1123n,1129n,1151n,1153n,1163n,1171n,1181n,1187n,1193n,1201n,1213n,1217n,1223n,1229n,1231n,1237n,1249n,1259n,1277n,1279n,1283n,1289n,1291n,1297n,1301n,1303n,1307n,1319n,1321n,1327n,1361n,1367n,1373n,1381n,1399n,1409n,1423n,1427n,1429n,1433n,1439n,1447n,1451n,1453n,1459n,1471n,1481n,1483n,1487n,1489n,1493n,1499n,1511n,1523n,1531n,1543n,1549n,1553n,1559n,1567n,1571n,1579n,1583n,1597n];for(let t=0;t<e.length&&e[t]<=n;t++){const r=e[t];if(n===r)return!0;if(n%r===0n)return!1}let r=0n;const o=n-1n;let i=o;for(;i%2n===0n;)i/=2n,++r;const s=o/2n**r;do{let t=c(w(o,2n),s,n);if(1n===t||t===o)continue;let e=1;for(;e<r&&(t=c(t,2n,n),t!==o);){if(1n===t)return!1;e++}if(t!==o)return!1}while(--t);return!0}let I=!1;self.Worker&&(I=!0);export{n as abs,t as bitLength,e as eGcd,r as gcd,f as isProbablyPrime,o as lcm,i as max,s as min,a as modInv,c as modPow,g as prime,l as primeSync,w as randBetween,h as randBits,m as randBitsSync,d as randBytes,B as randBytesSync,u as toZn};
+function n(n){return(n=BigInt(n))>=0n?n:-n}function t(n){if(1n===(n=BigInt(n)))return 1;let t=1;do{t++}while((n>>=1n)>1n);return t}function e(n,t){if((n=BigInt(n))<=0n|(t=BigInt(t))<=0n)throw new RangeError("a and b MUST be > 0");let e=0n,r=1n,o=1n,i=0n;for(;0n!==n;){const s=t/n,a=t%n,f=e-o*s,u=r-i*s;t=n,n=a,e=o,r=i,o=f,i=u}return{g:t,x:e,y:r}}function r(t,e){if(t=n(t),e=n(e),0n===t)return e;if(0n===e)return t;let r=0n;for(;!(1n&(t|e));)t>>=1n,e>>=1n,r++;for(;!(1n&t);)t>>=1n;do{for(;!(1n&e);)e>>=1n;if(t>e){const n=t;t=e,e=n}e-=t}while(e);return t<<r}function o(t,e){return t=BigInt(t),e=BigInt(e),0n===t&&0n===e?BigInt(0):n(t*e)/r(t,e)}function i(n,t){return(n=BigInt(n))>=(t=BigInt(t))?n:t}function s(n,t){return(n=BigInt(n))>=(t=BigInt(t))?t:n}function a(n,t){const r=e(u(n,t),t);if(1n!==r.g)throw new RangeError(`${n.toString()} does not have inverse modulo ${t.toString()}`);return u(r.x,t)}function f(t,e,r){if(0n===(r=BigInt(r)))throw new RangeError("n must be > 0");if(1n===r)return BigInt(0);if(t=u(t,r),(e=BigInt(e))<0n)return a(f(t,n(e),r),r);let o=1n;for(;e>0;)e%2n===1n&&(o=o*t%r),e/=2n,t=t**2n%r;return o}function u(n,t){return(t=BigInt(t))<=0?NaN:(n=BigInt(n)%t)<0?n+t:n}function c(n,t=16,e=!1){if("number"==typeof n&&(n=BigInt(n)),n<0)throw RangeError("w MUST be >= 0");return new Promise((e,r)=>{const o=new Worker(b());o.onmessage=n=>{o.terminate(),e(n.data.isPrime)},o.onmessageerror=n=>{r(n)},o.postMessage({rnd:n,iterations:t,id:0})})}function g(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");if(!I){let e=0n;do{e=$(m(n,!0))}while(!B(e,t));return new Promise(n=>{n(e)})}return new Promise(e=>{const r=[],o=(o,i)=>{if(o.isPrime){for(let n=0;n<r.length;n++)r[n].terminate();for(;r.length;)r.pop();e(o.value)}else{const e=$(m(n,!0));try{i.postMessage({rnd:e,iterations:t,id:o.id})}catch(n){}}};{const n=b();for(let t=0;t<self.navigator.hardwareConcurrency-1;t++){const t=new Worker(n);t.onmessage=n=>o(n.data,t),r.push(t)}}for(let e=0;e<r.length;e++)h(n,!0).then((function(n){const o=$(n);r[e].postMessage({rnd:o,iterations:t,id:e})}))})}function l(n,t=16){if(n<1)throw new RangeError("bitLength MUST be > 0");let e=0n;do{e=$(m(n,!0))}while(!B(e,t));return e}function w(n,e=1n){if(n<=0n||e<0n||n<=e)throw new RangeError("Arguments MUST be: max > 0 && min >=0 && max > min");const r=n-e,o=t(r);let i;do{i=$(m(o))}while(i>r);return i+e}function h(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=Math.ceil(n/8),r=n%8;return new Promise(n=>{d(e,!1).then((function(e){if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}n(e)}))})}function m(n,t=!1){if(n<1)throw new RangeError("bitLength MUST be > 0");const e=S(Math.ceil(n/8),!1),r=n%8;if(r&&(e[0]=e[0]&2**r-1),t){const n=r?2**(r-1):128;e[0]=e[0]|n}return e}function d(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");return new Promise((function(e,r){{const r=new Uint8Array(n);self.crypto.getRandomValues(r),t&&(r[0]=128|r[0]),e(r)}}))}function S(n,t=!1){if(n<1)throw new RangeError("byteLength MUST be > 0");{const e=new Uint8Array(n);return self.crypto.getRandomValues(e),t&&(e[0]=128|e[0]),e}}function $(n){let t=0n;for(const e of n.values()){const n=BigInt(e);t=(t<<BigInt(8))+n}return t}function b(){let n=`'use strict';const ${e.name}=${e.toString()};const ${a.name}=${a.toString()};const ${f.name}=${f.toString()};const ${u.name}=${u.toString()};const ${m.name}=${m.toString()};const ${S.name}=${S.toString()};const ${w.name}=${w.toString()};const ${c.name}=${B.toString()};${t.toString()}${$.toString()}`;return n+=`onmessage = ${async function(n){const t=await c(n.data.rnd,n.data.iterations);postMessage({isPrime:t,value:n.data.rnd,id:n.data.id})}.toString()};`,function(n){n=`(() => {${n}})()`;const t=new Blob([n],{type:"text/javascript"});return window.URL.createObjectURL(t)}(n)}function B(n,t=16){if(2n===n)return!0;if(0n===(1n&n)||1n===n)return!1;const e=[3n,5n,7n,11n,13n,17n,19n,23n,29n,31n,37n,41n,43n,47n,53n,59n,61n,67n,71n,73n,79n,83n,89n,97n,101n,103n,107n,109n,113n,127n,131n,137n,139n,149n,151n,157n,163n,167n,173n,179n,181n,191n,193n,197n,199n,211n,223n,227n,229n,233n,239n,241n,251n,257n,263n,269n,271n,277n,281n,283n,293n,307n,311n,313n,317n,331n,337n,347n,349n,353n,359n,367n,373n,379n,383n,389n,397n,401n,409n,419n,421n,431n,433n,439n,443n,449n,457n,461n,463n,467n,479n,487n,491n,499n,503n,509n,521n,523n,541n,547n,557n,563n,569n,571n,577n,587n,593n,599n,601n,607n,613n,617n,619n,631n,641n,643n,647n,653n,659n,661n,673n,677n,683n,691n,701n,709n,719n,727n,733n,739n,743n,751n,757n,761n,769n,773n,787n,797n,809n,811n,821n,823n,827n,829n,839n,853n,857n,859n,863n,877n,881n,883n,887n,907n,911n,919n,929n,937n,941n,947n,953n,967n,971n,977n,983n,991n,997n,1009n,1013n,1019n,1021n,1031n,1033n,1039n,1049n,1051n,1061n,1063n,1069n,1087n,1091n,1093n,1097n,1103n,1109n,1117n,1123n,1129n,1151n,1153n,1163n,1171n,1181n,1187n,1193n,1201n,1213n,1217n,1223n,1229n,1231n,1237n,1249n,1259n,1277n,1279n,1283n,1289n,1291n,1297n,1301n,1303n,1307n,1319n,1321n,1327n,1361n,1367n,1373n,1381n,1399n,1409n,1423n,1427n,1429n,1433n,1439n,1447n,1451n,1453n,1459n,1471n,1481n,1483n,1487n,1489n,1493n,1499n,1511n,1523n,1531n,1543n,1549n,1553n,1559n,1567n,1571n,1579n,1583n,1597n];for(let t=0;t<e.length&&e[t]<=n;t++){const r=e[t];if(n===r)return!0;if(n%r===0n)return!1}let r=0n;const o=n-1n;let i=o;for(;i%2n===0n;)i/=2n,++r;const s=o/2n**r;do{let t=f(w(o,2n),s,n);if(1n===t||t===o)continue;let e=1;for(;e<r&&(t=f(t,2n,n),t!==o);){if(1n===t)return!1;e++}if(t!==o)return!1}while(--t);return!0}let I=!1;self.Worker&&(I=!0);export{n as abs,t as bitLength,e as eGcd,r as gcd,c as isProbablyPrime,o as lcm,i as max,s as min,a as modInv,f as modPow,g as prime,l as primeSync,w as randBetween,h as randBits,m as randBitsSync,d as randBytes,S as randBytesSync,u as toZn};
diff --git a/lib/index.browser.mod.js b/lib/index.browser.mod.js
index 8046cc4..ff98fab 100644
--- a/lib/index.browser.mod.js
+++ b/lib/index.browser.mod.js
@@ -39,6 +39,8 @@ function bitLength (a) {
  * @param {number|bigint} a
  * @param {number|bigint} b
  *
+ * @throws {RangeError} a and b MUST be > 0
+ *
  * @returns {egcdReturn} A triple (g, x, y), such that ax + by = g = gcd(a, b).
  */
 function eGcd (a, b) {
@@ -152,18 +154,16 @@ function min (a, b) {
  * @param {number|bigint} a The number to find an inverse for
  * @param {number|bigint} n The modulo
  *
- * @returns {bigint|NaN} the inverse modulo n or NaN if it does not exist
+ * @throws {RangeError} a does not have inverse modulo n
+ *
+ * @returns {bigint} the inverse modulo n
  */
 function modInv (a, n) {
-  try {
-    const egcd = eGcd(toZn(a, n), n)
-    if (egcd.g !== 1n) {
-      return NaN // modular inverse does not exist
-    } else {
-      return toZn(egcd.x, n)
-    }
-  } catch (error) {
-    return NaN
+  const egcd = eGcd(toZn(a, n), n)
+  if (egcd.g !== 1n) {
+    throw new RangeError(`${a.toString()} does not have inverse modulo ${n.toString()}`) // modular inverse does not exist
+  } else {
+    return toZn(egcd.x, n)
   }
 }
 
@@ -178,7 +178,7 @@ function modInv (a, n) {
  */
 function modPow (b, e, n) {
   n = BigInt(n)
-  if (n === 0n) { return NaN } else if (n === 1n) { return BigInt(0) }
+  if (n === 0n) { throw new RangeError('n must be > 0') } else if (n === 1n) { return BigInt(0) }
 
   b = toZn(b, n)
 
diff --git a/lib/index.node.js b/lib/index.node.js
index a602bff..79a2112 100644
--- a/lib/index.node.js
+++ b/lib/index.node.js
@@ -41,6 +41,8 @@ function bitLength (a) {
  * @param {number|bigint} a
  * @param {number|bigint} b
  *
+ * @throws {RangeError} a and b MUST be > 0
+ *
  * @returns {egcdReturn} A triple (g, x, y), such that ax + by = g = gcd(a, b).
  */
 function eGcd (a, b) {
@@ -154,18 +156,16 @@ function min (a, b) {
  * @param {number|bigint} a The number to find an inverse for
  * @param {number|bigint} n The modulo
  *
- * @returns {bigint|NaN} the inverse modulo n or NaN if it does not exist
+ * @throws {RangeError} a does not have inverse modulo n
+ *
+ * @returns {bigint} the inverse modulo n
  */
 function modInv (a, n) {
-  try {
-    const egcd = eGcd(toZn(a, n), n)
-    if (egcd.g !== 1n) {
-      return NaN // modular inverse does not exist
-    } else {
-      return toZn(egcd.x, n)
-    }
-  } catch (error) {
-    return NaN
+  const egcd = eGcd(toZn(a, n), n)
+  if (egcd.g !== 1n) {
+    throw new RangeError(`${a.toString()} does not have inverse modulo ${n.toString()}`) // modular inverse does not exist
+  } else {
+    return toZn(egcd.x, n)
   }
 }
 
@@ -180,7 +180,7 @@ function modInv (a, n) {
  */
 function modPow (b, e, n) {
   n = BigInt(n)
-  if (n === 0n) { return NaN } else if (n === 1n) { return BigInt(0) }
+  if (n === 0n) { throw new RangeError('n must be > 0') } else if (n === 1n) { return BigInt(0) }
 
   b = toZn(b, n)
 
diff --git a/src/js/bigint-mod-arith.js b/src/js/bigint-mod-arith.js
index b17000e..962f281 100644
--- a/src/js/bigint-mod-arith.js
+++ b/src/js/bigint-mod-arith.js
@@ -39,6 +39,8 @@ export function bitLength (a) {
  * @param {number|bigint} a
  * @param {number|bigint} b
  *
+ * @throws {RangeError} a and b MUST be > 0
+ *
  * @returns {egcdReturn} A triple (g, x, y), such that ax + by = g = gcd(a, b).
  */
 export function eGcd (a, b) {
@@ -152,18 +154,16 @@ export function min (a, b) {
  * @param {number|bigint} a The number to find an inverse for
  * @param {number|bigint} n The modulo
  *
- * @returns {bigint|NaN} the inverse modulo n or NaN if it does not exist
+ * @throws {RangeError} a does not have inverse modulo n
+ *
+ * @returns {bigint} the inverse modulo n
  */
 export function modInv (a, n) {
-  try {
-    const egcd = eGcd(toZn(a, n), n)
-    if (egcd.g !== 1n) {
-      return NaN // modular inverse does not exist
-    } else {
-      return toZn(egcd.x, n)
-    }
-  } catch (error) {
-    return NaN
+  const egcd = eGcd(toZn(a, n), n)
+  if (egcd.g !== 1n) {
+    throw new RangeError(`${a.toString()} does not have inverse modulo ${n.toString()}`) // modular inverse does not exist
+  } else {
+    return toZn(egcd.x, n)
   }
 }
 
@@ -178,7 +178,7 @@ export function modInv (a, n) {
  */
 export function modPow (b, e, n) {
   n = BigInt(n)
-  if (n === 0n) { return NaN } else if (n === 1n) { return BigInt(0) }
+  if (n === 0n) { throw new RangeError('n must be > 0') } else if (n === 1n) { return BigInt(0) }
 
   b = toZn(b, n)
 
diff --git a/test/modInv.js b/test/modInv.js
index c1964ac..23af0d1 100644
--- a/test/modInv.js
+++ b/test/modInv.js
@@ -21,21 +21,20 @@ const inputs = [
     a: BigInt(-2),
     n: BigInt(5),
     modInv: BigInt(2)
-  },
+  }]
+
+const invalidInputs = [
   {
     a: BigInt(2),
-    n: BigInt(4),
-    modInv: NaN
+    n: BigInt(4)
   },
   {
     a: BigInt(0),
-    n: BigInt(0),
-    modInv: NaN
+    n: BigInt(0)
   },
   {
     a: BigInt(0),
-    n: BigInt(37),
-    modInv: NaN
+    n: BigInt(37)
   }
 ]
 
@@ -49,4 +48,16 @@ describe('modInv', function () {
       })
     })
   }
+  for (const input of invalidInputs) {
+    describe(`modInv(${input.a}, ${input.n})`, function () {
+      it('should throw RangeError', function () {
+        try {
+          _pkg.modInv(input.a, input.n)
+          throw new Error('should have failed')
+        } catch (err) {
+          chai.expect(err).to.be.instanceOf(RangeError)
+        }
+      })
+    })
+  }
 })
diff --git a/test/modPow.js b/test/modPow.js
index 96eee29..c1ae5b0 100644
--- a/test/modPow.js
+++ b/test/modPow.js
@@ -7,12 +7,6 @@ const chai = require('chai')
 // <--
 
 const inputs = [
-  {
-    a: BigInt(4),
-    b: BigInt(-1),
-    n: BigInt(0),
-    modPow: NaN
-  },
   {
     a: BigInt(4),
     b: BigInt(-1),
@@ -42,6 +36,13 @@ const inputs = [
     b: BigInt(3),
     n: BigInt(25),
     modPow: BigInt(2)
+  }]
+
+const invalidInputs = [
+  {
+    a: BigInt(4),
+    b: BigInt(-1),
+    n: BigInt(0)
   }
 ]
 
@@ -55,6 +56,18 @@ describe('modPow', function () {
       })
     })
   }
+  for (const input of invalidInputs) {
+    describe(`modPow(${input.a}, ${input.b}, ${input.n})`, function () {
+      it('should throw RangeError', function () {
+        try {
+          _pkg.modPow(input.a, input.b, input.n)
+          throw new Error('should have failed')
+        } catch (err) {
+          chai.expect(err).to.be.instanceOf(RangeError)
+        }
+      })
+    })
+  }
   describe('Time profiling', function () {
     let iterations = 500
     it(`just testing ${iterations} iterations of a big modular exponentiation (1024 bits)`, function () {
diff --git a/types/index.d.ts b/types/index.d.ts
index a9f4b88..da83b73 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -34,6 +34,8 @@ export function bitLength(a: number | bigint): number;
  * @param {number|bigint} a
  * @param {number|bigint} b
  *
+ * @throws {RangeError} a and b MUST be > 0
+ *
  * @returns {egcdReturn} A triple (g, x, y), such that ax + by = g = gcd(a, b).
  */
 export function eGcd(a: number | bigint, b: number | bigint): egcdReturn;
@@ -91,9 +93,11 @@ export function min(a: number | bigint, b: number | bigint): bigint;
  * @param {number|bigint} a The number to find an inverse for
  * @param {number|bigint} n The modulo
  *
- * @returns {bigint|NaN} the inverse modulo n or NaN if it does not exist
+ * @throws {RangeError} a does not have inverse modulo n
+ *
+ * @returns {bigint} the inverse modulo n
  */
-export function modInv(a: number | bigint, n: number | bigint): number | bigint;
+export function modInv(a: number | bigint, n: number | bigint): bigint;
 /**
  * Modular exponentiation b**e mod n. Currently using the right-to-left binary method
  *