Prime Number Checker

A prime number is a whole number greater than 1 that has exactly two positive divisors: 1 and itself. 7 is prime because nothing else divides it evenly; 9 is not, because 3 divides it. Numbers with more than two divisors are called composite.

No. 1 is a unit and 0 is special — both are neither prime nor composite. By definition a prime must be greater than 1 and have exactly two divisors, which 0 and 1 do not, so the checker labels them accordingly.

For a composite number it lists the prime building blocks and how many times each one is used. For example 360 factors as 2^3 × 3^2 × 5, and multiplying those back gives 360. For a prime, the factorization is just the number itself.

Yes. To stay fast and responsive in your browser, the checker accepts whole numbers up to 1,000,000,000,000 (one trillion). Larger values are reported as too large to check rather than freezing the page.