PHP; factorize any integer

gistfile1.txt

<?php
/*
$ php factorize.php 90
Array
(
    [2] => 45
    [3] => 30
    [5] => 18
    [6] => 15
    [9] => 10
    [10] => 9
)
*/

$i++;while($i++<sqrt($a=$argv[1]))!($a%$i)?$b[$i]=$a/$i:'';print_r($b);