- array_sum: documentation ( source)
- printf: documentation ( source)
<?php
function x($n) {
for($i = 1; $i <= $n; $i++) {
$n % $i == 0 && $i != $n ? $factors[]=$i & printf("$i ") : 0;
}
array_sum($factors) == $n ? printf('P') : printf('I');
}
x(28);