Kod uzyskania sum cyfr

<?php
    
    $num = 3434654567;
    $rem = 0;
    $sum = 0;
    for($i = 0; $i <= strlen($num); $i++) {
      $rem = $num % 10;
      $sum = $sum + $rem;
      $num = $num/10;
    }
    echo "Sum of digits is $sum";
    
  ?>
Outrageous Ostrich