… perfect, abundant, wasteful, happy (and unhappy), narcissistic, amenable, automorphic, trimorphic, and self-descriptive.
Not to mention Fibonacci Numbers, Lucas Numbers, VR Numbers, and — I’m not making this up — Vampire Numbers.
I remember from my own elementary school days that the number 1 is unique (as the only number with one divisor). 0, as far as I can tell, was always a problem child (and indeed, mathematicians talk longingly of Zerofree Numbers). But you’d be a problem child, too, if every time you tried to divide yourself into a larger number someone came along and said, “No, no, no, you can’t do that, you’ll make the whole problem undefined, and we couldn’t have that.”
From MathWorld, found by way of the What Makes This Number Special list sent to me by lnhammer. (Every number is special, of course. Except for 226, 234, 241, 249, and 250. And 0.)