How to list play store apps by number of downloads?
You can't do this on the Play Store itself, but there's a website that will do the job perfectly.
It's by 42Matters, and it's called the App Market Explorer. You can view either the Google Play Store or the Apple App Store. It's a powerful search, where you can search by ratings, downloads, and price, among other factors.
Check it out; I bet this is exactly what you needed!
i think google does not do that because for example Free applications get more downloads than paid applications combining with fake downloads, ratings... Perhaps I am Wrong