Once upon a time, when I was training to be a mathematician,

Once upon a time, when I was training to be a mathematician, a group of
us bright young students taking number theory discovered the names of
the smaller prime numbers.

2: The Odd Prime --
It's the only even prime, therefore is odd. QED.
3: The True Prime --
Lewis Carroll: "If I tell you three times, it's true."
31: The Arbitrary Prime --
Determined by unanimous unvote. We needed an arbitrary prime
in case the prof asked for one, and so had an election. 91
received the most votes (well, it *looks* prime) and 3+4i the
next most. However, 31 was the only candidate to receive none
at all.

Since the composite numbers are formed from primes, their qualities are
derived from those primes. So, for instance, the number 6 is "odd but
true", while the powers of 2 are all extremely odd numbers.