Mnumerimonic
I knew a woman once with the nickname “Sproidy‖she was given this monicker because the letters on the dial of the phone could be used to spell that. I occasionally find myself using this trick in reverse when I need to invent a numeric passcode or the like–I pick a convenient word, and work out the numbers on a phone dial that correspond to it.
There ought to be a name for words and numbers created using this trick, of using numbers to generate words, or vice-versa. Since these are generally used as an aide-memoire, I kind of like “mnumerimonic.†Another possibility might be “numerinym,†though that would only make sense for to words generated from numbers.