I predict over 10 million downloads first week, 1 billion + downloads lifetime.

EDIT: I should add some extra perspective here. Pokemon sells tens of millions on a dedicated, standalone platform. Scale the userbase to practically the whole world and nearly all smart devices (sorry Microsoft), and make it free for everyone - you got a BILLION downloads. 

I'm not joking around here. Angry Birds and Temple Run started with no IP recognition, Pokemon has it in spades.

Not quite a week yet, and it's at 7.5 million in the US alone.

https://techcrunch.com/2016/07/11/pokemon-go-daily-revenue-downloads/

edit december 2016:

I was right about the initial download count. My 1 billion lifetime download count prediction is steadily on track to become true.

Polygon reported back in September Pokemon Go has been downloaded 500 million times now already. Given the kind of support the app is getting, and the still active user base left behind it, I will inevitably be proven right about the 1 billion download count.

http://www.polygon.com/pokemon-go/2016/9/7/12836898/pokemon-go-downloads-500-million

I predict your prediction will be wrong.

It will break the appstore.

It is gonna be interesting how well it does in Japan alone.

I don't see a billion downloads ... that's quite a bit, how many games have even done that?

Billion lifetime is completely unrealistic. I would say 50 million tops.

Make a prediction yourself!

Well, Ingress by itself has had more than 10,000,000 downloads. Attach the Pokémon name to it, make it free, make it cool... Yeah, at least some 5,000,000 first week.

If brilliantly marketed this series and animal crossing could do wonders on the mobile platform and bring Nintendo to interesting profit margins.

Temple Run, several Angry Birds games, Candy Crush, Clash of Clans