maebuf:

You've already received some good comments. I'll just make a couple here:

• In your loop, you're doing a divide and a modulus every iteration. You could do the divide only when the modulus leaves no remainder.
• You don't really need to store the result of the modulus in a variable since you're using it only in your if statement. So you could just move the calculation to your if statement.
• Similarly, you're creating an array from a sequence, and then using the sequence only in one place. You could put the sequence in the for loop where you use it.

Putting those together would give you:

foreach $int (1 .. ($no/2)) {
   if ($no%int == 0) {
      $div = $no / $int;
      print "$div\n";
   }
}
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Algorithmically, you're doing quite a few operations that will *never* give you a factor, because your sequence includes even numbers other than two. You could generate a list that includes 2 and all the odd numbers up through half of the input number like this:

foreach $int (2, map {$_*2+1} (1 .. ($no/4)) {
  ....
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I hope you find it helpful.

...roboticus

Update: If you want to crunch the code down, you could even combine most of it to a single statement:

print "$_\n" for grep { 0==$no%$_ } (2, map { 2*$_+1 } 1 .. $no/2);
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Note: Another thing to watch for is that you're not restricting yourself to prime factors. I don't know if it matters to you, though.