(PHP 5 >= 5.2.0, PHP 7, PHP 8)
gmp_nextprime — Find next prime number
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 the next prime number greater than num,
as a GMP number.
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
Note:
This function uses a probabilistic algorithm to identify primes and chances to get a composite number are extremely small.