You are #3635. Rumble is #1189.
Go to any thread you've posted in, point at your name (along the left hand side, where it shows your post) and there's a link that ends in "?u=***". The "***" is your member number. Or you can go to the memberlist, find yourself and do the same thing - point your mouse pointer at your name, look at the link in the status bar or just click on it, then look at the URL in the address bar.