Prime number

Revision as of 17:31, 19 June 2006 by Fedja (talk | contribs) (merged Prime and Prime number articles and set the redirect)

A prime number (or simply prime) is a positive integer $p>1$ whose only positive divisors are 1 and itself. Note that $1$ is usually defined as being neither prime nor composite because it is its only factor among the natural numbers.

Advanced Definition

When the need arises to include negative divisors, a prime is defined as an integer p whose only divisors are 1, -1, p, and -p.