PHP Program - Find the largest prime factor of a number

  number = num

  Step 1: If num is divisible by 2, store
  largest prime factor as 2. keep on dividing
  num until it is not divisible by 2. After
  each division, update num as num/2.

  Step 2: At this point, num must be odd.
  Starting with 3 to square root of num, if
  divisible, divide and update num, and update
  largest prime factor.

  Step 3: if the modified num is greater than
  2, update the largest prime factor with num.

<?php
function MaxPrime($num) {
  $CurrMaxPrime = -1;

  //If $num is divisible by 2, store $CurrMaxPrime
  //as 2. keep on dividing $num until it is not 
  //divisible by 2. After each division, update 
  //$num as $num/2.
  if($num % 2 == 0) {
    $CurrMaxPrime = 2;
    while($num % 2 == 0){
      $num = $num/2;
    }
  }
  
  //At this point, $num must be odd. Starting with 
  //3 to square root of $num , if divisible, divide 
  //and update $num, and update $CurrMaxPrime
  for($i = 3; $i <= sqrt($num); $i += 2) {
    while($num % $i == 0) {
      $CurrMaxPrime = $i;
      $num = $num/$i;
    }
  }

  //if the modified $num is greater than 2, 
  //update the $CurrMaxPrime with $num 
  if ($num > 2) 
    $CurrMaxPrime = $num;

  return $CurrMaxPrime;
}

$x = 42;
$y = 1092;
$z = 695467363456;

echo "Largest prime factor of $x is: "
     .MaxPrime($x)."\n";
echo "Largest prime factor of $y is: "
     .MaxPrime($y)."\n";
echo "Largest prime factor of $z is: "
     .MaxPrime($z)."\n";
?>