Are there really 1.6 billion Muslims on this planet?

Many people say Islam will become the largest religion by 2050.

Here's the thing. The 1.6 billion Muslim figure is made up of Shias, Sunnis, Ismailis, Sufis, Salafis/Wahabis, Ahmadiyya's, and Quran alone. Sunnis and Shias don't see each other as Muslim, Shias and Sunnis don't see Ismailis and Sufis as Muslim, Shias and Sunnis don't see the Quran alone group as Muslims, Ahmadiiyas are not seen as Muslim by anybody, and the Salafis/Wahabis don't see anybody but themselves as Muslim. So how can there really be 1.6 billion Muslims?

I have mentioned the 25 types of people who really should not exist in the ummah (http://mymuslimthoughts.blogspot.ca/2015/02/the-idiots-who-should-not-exist-in-our.html) but they do. These people unfortunately exist in our religion, and they add to the 1.6 billion number.

Makes me think, would many Muslims (me included) accept a much smaller number of worldwide Muslims if we could kick out the idiots who shame us on a daily basis?