The number of bitcoin users is 2.5 millions. I found this information couple months ago on the net. But I think during this couple months the number increased. Bitcoin as money and as technology are getting more and more popular and used in daily life.
I can hardly believe in that, there are no more than one million of real users; I personally don't know anyone, except me, who uses Bitcoin, not to speak of alts. Many heard about it but nobody ever purchase it 