// 4 ^ 1 + 6 ^ 2 + 9 ^ 3 + 8 ^ 4 = 4 + 36 + 729 + 4096 = 4865
$num = 4698;
$len = strlen((string)abs($num));
$sum = 0.0;
$temp = $num;
while ($temp > 0) {
$remainder = $temp % 10;
$sum = $sum + pow($remainder, $len);
$temp = (int)($temp / 10);
$len--;
}
echo $sum;
/*
run:
4865
*/