Actually I don't know how many altcoin are in the cryptocurrency world. but i know just listed on coinmarketcap have more then 1320 types altcoin.
Just you see here:
https://coinmarketcap.com/all/views/all/Yes I see this article.But as much I know all currency can't get chance to added on coinmarketcap.Because it is a big coin market.So I want more information.
By the way, thanks for this information.