Dear Bitter Amanda,
What is the proper response to a man-child that asks for your number before he asks for your name?
Well clearly your best course of action is to make him feel like the drooling, grunting caveman that he is. Allow me to model a conversation for you. Please note that depending on his level of evolution, he may or may not get that you're calling him a moron. Even if he doesn't, though, it'll hit him later as he relays it to friends, perplexed.
The Missing Link: "Can I have your number? *grunt*"
Your Royal Hotness: "Hi, I'm *insert name here*."
YRH: "Nice to meet you."
TML: "Whaaa? Number? No?"
You see what I did there? You play out the conversation as though he'd properly introduced himself first. In doing so, it's thrown him off his course, because he didn't hear any numbers. Then you can give him a phone number--check out this page. It's called The Rejection Hotline, and it's a real number you can give someone, but it leads them to a recording about how they just got hardcore turned down. I've never used it, but it sounds like good fun!
Best of luck, buttercup.