Category 9 — Cryptography / Security
Compute GCD, LCM, Euler's totient, coprime check, and prime factorization for two integers.
Number A and Number B fields — results update automatically as you type.Shared Properties grid for GCD(A, B), LCM(A, B), the coprime answer (Yes/No), and their product.Number A and Number B for each value's φ(n) (Euler's totient) and prime factorization.84 & 18, 100 & 25, or 65537 & 17 — to load a preset pair instantly.Enter two positive integers or Numbers must be positive.The GCD divides numerator and denominator to lowest terms, while the LCM finds a shared denominator or a common time interval.
In RSA the public exponent e must be coprime to φ(n). The coprime check confirms gcd = 1 before you commit to parameters.
Used across cryptography and number theory — for primes p and q, φ(p·q) = (p−1)(q−1). This tool returns it directly for each input.
Prime factorization underpins the hardness of RSA and many proofs. See each number broken into its prime-power form (2^2 × 3 × 7).
All math runs on JavaScript BigInt, so huge values stay exact instead of silently rounding like floating point would.
Everything computes locally in your browser. Nothing is uploaded, logged, or sent to a server — safe for working with key material.
For two integers it returns their GCD, LCM, whether they are coprime, and their product, plus φ(n) (Euler's totient) and the prime factorization of each number.
The greatest common divisor is the largest integer that divides both numbers evenly. It's computed with the Euclidean algorithm and is the basis for reducing fractions to lowest terms.
φ(n) counts the positive integers up to n that are coprime to n. For example φ(9) = 6. It's central to RSA key generation and modular arithmetic.
Two numbers are coprime when their only common divisor is 1 — that is, gcd(A, B) = 1. It doesn't require either number to be prime.
Yes. Computations use JavaScript BigInt, so there's no floating-point rounding — the results stay exact even for large values.
The tool only accepts positive integers. Empty fields, negative numbers, decimals, fractions, or non-digit characters are rejected and the results area is hidden until valid input is entered.
Never. All number-theory calculations happen locally in JavaScript. Your values are not sent to, stored on, or logged by any server.