// Strong numbers are the numbers that the sum of factorial of its digits
// is equal to the original number
// 145 is a strong number: 1 + 24 + 120 = 145
$n = 145;
$sum = 0;
$tmp = $n;
while ($n != 0)
{
$reminder = $n % 10;
$sum = $sum + factorial($reminder);
$n = (int)($n / 10);
}
if ($sum == $tmp)
echo $tmp . " is a strong number<br />";
else
echo $tmp . " is not a strong number<br />";
function factorial($n)
{
$fact = 1;
for ($i = 2; $i <= $n; $i++)
$fact = $fact * $i;
return $fact;
}
/*
run:
145 is a strong number
*/