A primary quantity is a optimistic integer better than 1 that has no optimistic divisors aside from 1 and itself. As an example, is 7 a chief quantity? The reply is sure, since 7 solely has two optimistic divisors: 1 and seven.
Figuring out whether or not a quantity is prime has sensible functions, together with cryptography, laptop science, and arithmetic. One of many first important historic developments in prime quantity idea was Euclid’s proof that there are infinitely many prime numbers.