With my SSN it took about 3 weeks to be received but at my appointment they gave a piece of paper to say to contact them after 4 weeks if it hadn't been received. Not sure if you got anything like that at your appointment? I did ring the local office sometime after 2 weeks and they told me it had been processed but couldn't give me the SSN over the phone for obvious reasons (I didn't ask them over the phone to give it to me though - she just told me after bringing up my details on the system) but I think if you need the number at least then you can go into your local SSA branch and ask them to provide it to you (if it has been processed yet that is).