While reading this, there were a few things I noticed.
1) This almost certainly a first novel (albeit a great attempt at one).
2) This would have improved greatly with the help of an editor.
3) From the description, this sounds like it would be a very plot driven novel, and it is in some ways, but it never truly abuses the possibilities of the "gimmick" of the story.
Despite these criticisms, this was a great read that I was able to speed through quickly.
The characters, even being a little strongly typed, were characters who kept focus easily and their interactions with each other were extremely well written, enough that the characters themselves pushed the novel along by themselves, with very little help from the plot.
The conversations themselves were natural and the settings were beyond vivid; the settings were experiential.
Humor in this book occurs quite often and it is for the most part funny. A few jokes, however, fall flat or simply aren't right for the novel format, and I think things like this would have been picked out by a professional editor.
None of these "bumps" really held the novel from shining through, however. The reason I took a star away (If I gave a more precise rating, it'd be a 4.2/5.0) was because the premise had such potential, yet the plot literally on focuses on it approximately half the time (and that half isn't even always following the essential aspect of the premise - the idea that everyone has a "number" attached to them). If that was ironed out, this would definitely be a masterpiece of a first novel.
As it stands, it is a great first novel, one I would highly recommend others to read.