"can someone be a hacker without knowing security?" of course not.
Depends on how you define hacker. I personally define it as someone who knows a particular system inside-out, whether that system is networking, being a good programmer or being an expert at hockey. That said, in a broader sense, yes someone could be a hacker and not know security. If I'm a game "hacker" and manipulate the game to create cheat codes and such, there's little security needed for that.

how many of the peole here are hackers?
Once you define what a hacker is, you probably can answer this question. I personally don't consider myself a hacker but rather look at myself as someone who is very curious about things and likes to solve problems. I still have a lot of learning to do before I'd ever put myself into that category.