Try searching around a bit. There are lots of threads on this, but i don’t blame you they are hard to find some times.
I don’t think that there are any legit requirements on words. They might not except it if it is too short though. Also if you don’t want every one who bought it hating you 150 000 words would be a good amount with a multiple ending game, but if it is linear i think it should have about double.