PHP Manual: Raise number into power with modulo

GMP gmp_powm(GMPintstring $num, GMPintstring $exponent, GMPintstring $modulus)

Calculate (num raised into power exponent) modulo modulus. If exponent is negative, result is undefined.

num

The base number.

A GMP object, an int or a numeric string.

exponent

The positive power to raise the num.

A GMP object, an int or a numeric string.

modulus

The modulo.

A GMP object, an int or a numeric string.

The new (raised) number, as a GMP number.

Example #1 gmp_powm example

<?php
$pow1 = gmp_powm("2", "31", "2147483649");
echo gmp_strval($pow1) . "\n";
?>

The above example will output:

2147483648