The Number Theory Tools cover prime factorization (up to 10¹²), LCM and GCD of multiple numbers, primality testing, modular arithmetic (including fast modular exponentiation), and Euler's totient function. Useful for competitive programming, cryptography and discrete mathematics.
Yes. The Number Theory Tools is completely free with no sign-up and no limits.
No. All calculations run in your browser using JavaScript. Nothing is sent to any server.
Yes. Once the page is loaded, all computations work without an internet connection.
Yes, it works in any modern browser on desktop, tablet and mobile.