I'm in the suburbs of Denver, about 10 miles North. I'm not sure about Denver proper. You do see a lot of it in the city limits. So I don't imagine there are any laws against it there. If there are, they aren't enforced for s**t.
Panhandling is protected speech in the US. If your city has tried to outlaw it in general, they will most likely be dragged to court, spend a lot of money, and lose.