If you're really a spektic then explain this:

[Aegon]

I can't give a source but I read it a while back on google.

It's just theoretical military math. With a population of over 1.2 billion people, China has a potential manpower base of another 200 million males. But there is no indication they are actually building up their army like that, and it would take extraordinary circumstances for them to.

What you're talking about is really just the largest theoretical active military they could create at their peak potential. It's something the defense industry says to scare Congress into giving them more money, not a genuine stat.