At first, many have thought it was 37. However, as people have pointed out, 3 + 7 = 10 /2 = 5, which is not even. I am sorry if the "even" is subject to misinterpretation, and next time (if I do have a next time) I won't just write even, but with an added note liek "even whole..." or "even (as in a number divisible by 2)" or something.
And wow... I agree with Jer. This "easy" question did spark some discussion.
One more point: Bravo to Charlie to be first to supply the answer, and to DJ to smooth all discussions out