$theInt = 1501299200;
$theHex = sprintf("%lx", $theInt);

$hexPairs = split(/(\w{1,2})/, $theHex);
while $val (@hexPairs)
{
   if (!$thisPair eq "" )
   {
      $finalHex .= "\x".$thisPair;
   }
}
$bytes .= pack("C/a*", $finalHex);