print date utc and convert date to time stamp

<?php
print gmdate("Y-m-d\TH:i:s\Z");

$utc=gmdate("Y-m-d\TH:i:s\Z");
echo "<br>";

echo strtotime($utc);

echo "<br>";

$fromunixtime_utc=gmdate("Y-m-d\TH:i:s\Z",strtotime($utc));

echo $fromunixtime_utc;

?>

2017-08-26T02:52:01Z
1503715921