Find if a Positive Integer is power of 2 , 3 , 4

is_Power_of_four.php

<?php

function is_Power_of_four($n)
{
      $x = $n;
      while ($x % 4 == 0) {
      $x /= 4;
     }
       
	if($x == 1)
    {
		return "$n is power of 4";
    }
    else
    {
		return "$n is not power of 4";
    }
  
}

print_r(is_Power_of_four(4)."\n");
print_r(is_Power_of_four(36)."\n");
print_r(is_Power_of_four(16)."\n");

?>

is_Power_of_three.php

<?php

function is_Power_of_three($n)
{
      $x = $n;
      while ($x % 3 == 0) {
      $x /= 3;
     }
       
	if($x == 1)
    {
		return "$n is power of 3";
    }
    else
    {
		return "$n is not power of 3";
    }
  
}

print_r(is_Power_of_three(9)."\n");
print_r(is_Power_of_three(81)."\n");
print_r(is_Power_of_three(21)."\n");

?>

is_Power_of_two.php

<?php

function is_Power_of_two($n)
{
   if(($n & ($n - 1)) == 0)
    {
		return "$n is power of 2";
    }
   else
    {
		return "$n is not power of 2";
    }
}

print_r(is_Power_of_two(4)."\n");
print_r(is_Power_of_two(36)."\n");
print_r(is_Power_of_two(16)."\n");

?>