Enter values and calculate.
Result
Method
Small prime divisors are checked first. Remaining values use a fixed seven-base Miller–Rabin test that is deterministic—not probabilistic—for unsigned 64-bit integers. BigInt arithmetic preserves every input digit.
Worked example
97 is prime. 221 is composite because 221 = 13 × 17. The values 0 and 1 are neither prime nor composite.
Limits and assumptions
Input must be a nonnegative integer no larger than 18,446,744,073,709,551,615 (2^64 − 1). This is a primality test, not a factor finder; use Prime Factorization when the factors themselves are needed.
Exactness and privacy
Supported integer calculations use BigInt and validated text, not floating-point Number conversion. Results are rendered as inert text. This educational calculator does not send calculation values to a server or make professional decisions for you.