PHP Manual: Find next prime number

Description

resource gmp_nextprime ( int $a )

Find next prime number

Parameters

a: It can be either a GMP number resource, or a numeric string given that it is possible to convert the latter to a number.

Return Values

Return the next prime number greater than a, as a GMP number.

Examples

Example #1 gmp_nextprime example


<?php
$prime1 = gmp_nextprime(10); // next prime number greater than 10
$prime2 = gmp_nextprime(-1000); // next prime number greater than -1000

echo gmp_strval($prime1) . "\n";
echo gmp_strval($prime2) . "\n";
?>

The above example will output:

11
-997

Notes

Note:
This function uses a probabilistic algorithm to identify primes and chances to get a composite number are extremely small.