The App555 site says there are 100,000, 1,000,000 or 5,000,000 downloads depending on what page you open up. If you want to download the app it redirects you to Google Play for the download. If it had been downloaded 5,000,000 times then Google Play would also show 5,000,000 downloads as that is the site you are actually downloading the app from.
This isn't rocket science anyone who bothers to click download and follow the links can see this for themselves. I have no idea why this is still being discussed. You should be sceptical of the fact App555 has 3 different download counts and your sceptisism can be confirmed by looking at the actual download count on Google Play.