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gmp_nextprime

(PHP 5 >= 5.2.0, PHP 7, PHP 8)

gmp_nextprime — Find next prime number

Description

gmp_nextprime(GMP|int|string $num): GMP

Find next prime number

Parameters

num: A GMP object, an int, or a string that can be interpreted as a number following the same logic as if the string was used in gmp_init() with automatic base detection (i.e. when base is equal to 0).

Return Values

Return the next prime number greater than num, 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
2

Notes

Note:

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

© 1997–2025 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.gmp-nextprime.php