It's not German. It's from the game Secret Exit. "owt neht ruof neht evif" is Five then four then two backwards.
In the simplest, two then four then five. This may be code for something, but for which I know not.
Hmm, Well for one thing, owt neht ruof neht evif, is NOT German, Go take a look in a mirror would you?
They're all numbers backwards
It says "answer this question backwards". Ans 2. This is "k-cab g-nals" which is seriously old-fashioned, even in London where it originated.