40979067. I don't even know how I remember. I haven't used ICQ for 15 years.
I no longer have access to the @r33t.org email address, nor do I know the password. Unfortunate.
edit: Looking at the profile it seems that a Russian hacked/took over the account who knows how long ago.
Thought about selling it on ebay, since six-digit accounts used to fetch a non-trivial amount of money. But decided it wasn't worth the $100.
But people had the habit of exchanging UIN and this was it.
24811423
Probably we remember because the client made you type it to log in? I forget, but I feel like this is true :)