int fileatime ( string $filename )

<?php
   echo fileatime("/PhpProject/sample.txt");
   echo "\n";
   echo "Last access: ".date("F d Y H:i:s.",fileatime("/PhpProject/sample.txt"));
?>

1590217956
Last access: May 23 2020 09:12:36.

<?php
   filename = "/PhpProject/sample.txt";
   if(file_exists(filename)) {
      echo "filename was last accessed at: " . date("F d Y H:i:s.", fileatime(filename));
   }
?>

/PhpProject/sample.txt was last accessed at: May 23 2020 09:12:36.