PHP: seconds to days mins hours

public function strTime($s) {
     $d = intval($s/86400);
     $s -= $d*86400;

     $h = intval($s/3600);
     $s -= $h*3600;

     $m = intval($s/60);
     $s -= $m*60;

     if ($d) $str = $d . ' day ';
     if ($h) $str .= $h . ' hour(s) ';
     if ($m) $str .= $m . ' minute(s) ';
     if ($s) $str .= $s . ' second(s)';

     return $str;
}