GMP
PHP Manual

gmp_nextprime

(PHP 5 >= 5.2.0)

gmp_nextprime — 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.


GMP
PHP Manual