HOW MANY MEN IN THE US ARMY?

I believe the last I saw it was around 1.7 million total if you include reservists, but that number may be off.

As of 12 Aug. 2017, there are 468,395 male Active Duty soldiers in the U.S. Army (and 71,280 females).

http://www.statisticbrain.com/demographics-of-active-duty-u-s-military/