Determine if an integer Z can be expressed in the form P^Q using PHP

superPower.php

<?php
  /**
   * Return 1 if $Z can be expressed as on integer raised to the power of another integer
   */
  function superPower( $Z) {

    $half = (int) sqrt($Z);
    
    for ($x=2; $x<$half; $x++) {
        if ($Z % $x == 0) {
			for ($y=1; $y<$half; $y++) {
				if (pow($x,$y) == $Z) {
					//echo "$x ^ $y = $Z";
					return 1;
				}	
			}   
        }
    }
    
    return 0;
  
  }
  
  echo superPower(25); // Should return 1
  echo superPower(26); // Should return 0
?>