- The definition of a prime number is a number that can only be evenly divided by 1 and itself.
An example of a prime number is the number 13, since it is evenly divisible only by 1 and 13.

## prime number

an integer that can be evenly divided by no other whole number than itself or 1, as 2, 3, 5, or 7

## prime number

noun

A positive integer that is greater than 1 and is not divisible without a remainder by any positive integer other than itself and 1.

## prime number

Noun

(*plural* prime numbers)

- (number theory) Any natural number greater than 1 divisible only by itself and 1.
*Every natural number greater than 1 can be factorized into prime numbers.*

Usage notes

- Modern mathematical usage specifies that 1 is not a prime number (as has been defined here); some older texts consider 1 to be a prime number.

Antonyms

- prime
- prime factor
- primality
- prime factorization

## prime number - Computer Definition

An integer greater than 1 that is not evenly divisible by any number other than itself, and, of course, 1. Prime numbers are considered a fundamental building block of numbers, especially number theory, a branch of mathematics. The first 10 prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23 and 29. Except for 2, all primes are odd numbers. As the numbers get higher, prime numbers tend to be found in pairs that are close together; for example, 29,669 and 29,671 are primes. The largest prime number thus far, which contains more than 65,000 digits, was discovered in 1986.