There is hardly anything optimised there (if not for what permutations might do under the hood instead of a function written to do the same by you) and it is actually rather brute-forceish; try to ask yourself how you would solve it as a human and I am sure you would not compute each single possibility, sort them, etc.

Also, please, try to format the code properly when posting it :)

[Incidentally, sorting str(n) would probably be much better than sorting result, but please do not go that way]

Just check how long your solution runs for input like 1987654321.