I love this word, enumeronym, though. It seems you may have coined it, as the only Google search result is your comment. The second may well be this comment. I hope it catches on!
Google suggests that the correct term is "numeronym" [1].
> According to Tex Texin, the first numeronym of this kind was "S12n", the electronic mail account name given to Digital Equipment Corporation (DEC) employee Jan Scherpenhuizen by a system administrator because his surname was too long to be an account name. By 1985, colleagues who found Jan's name unpronounceable often referred to him verbally as "S12n" (ess-twelve-en). The use of such numeronyms became part of DEC corporate culture.