$date = new DateTime();
echo $date->getTimestamp();
<?php
$date = new DateTime();
echo $date->format('U = Y-m-d H:i:s') . "\n";
$date->setTimestamp(1171502725);
echo $date->format('U = Y-m-d H:i:s') . "\n";
?>
$ts = 1171502725;
$date = new DateTime("@$ts");