An integer greater than 1 is prime if its only positive integer divisors are 1 and itself. Otherwise, it is composite. Prime numbers are central elements of number theory, established as such by the fundamental theorem of arithmetic, which recognizes that all integers greater than 1 can be decomposed into unique products of primes. Wolfram|Alpha has many tools for working with primes and related ideas.
Check numbers for primality. Generate prime numbers or lists of prime numbers meeting certain conditions.
Determine whether a number is prime:
Specify a prime by its position in the sequence 2, 3, 5, ...:
Generate a list of primes:
Find the nearest prime to a given number:
Work with special subsets of prime numbers. Find numbers within these sets or check for membership.
Find a twin prime pair:
Find a Mersenne prime:
Find one of the few known Fermat primes:
Decompose numbers into products of primes, which are unique per the fundamental theorem of arithmetic.