Check whether a number is prime, see its prime factorization, and find the nearest prime numbers before and after it.
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A prime number is a whole number greater than 1 with no divisors other than 1 and itself. This calculator checks primality by trial division, testing whether any number up to the square root of your input divides evenly into it. If none do, the number is prime.
Every whole number greater than 1 can be broken down into a unique product of prime numbers, called its prime factorization. This calculator repeatedly divides your number by the smallest possible prime factor until only 1 remains, listing each prime factor found along the way.
No, by definition a prime number must have exactly two distinct positive divisors: 1 and itself. The number 1 has only one divisor, so it's neither prime nor composite.
This calculator supports positive whole numbers up to 100,000,000. Very large numbers would take too long to check using this method in a browser.
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