Python tricks 101

The trick to reverse a number is probably awfully slow.

  print(int(str(num)[::-1]))

Unless the Python compiler has a huge bigger amount of magic than what I imagine is possible, this code is very slow.

It's not so bad if you run it once, but if you put it inside a thigh loop, the performance would be awful. Never ever use a string to transform a number into another number in any language.

Perhaps you can try to make a post with a benchmark comparing this method and another method that only use integer division (and perhaps other that use floating point division).

Please read the guidelines on how to submit on this site.

You should have filled the URL field, not the text field. Like you did three days ago, that was good.