From the article Number Theory in the 1994 Microsoft Encarta: "If a, b, c are
integers such that a = bc, a is called a multiple of b or of c, and b or c is
called a divisor or factor of a. If c is not 1/-1, b is called a proper divisor
of a. Even integers, which include 0, are multiples of 2, for example, -4, 0,
2, 10; an odd integer is an integer that is not even, for example, -5, 1, 3, 9.
A perfect number is a positive integer that is equal to the sum of all its positive,
proper divisors; for example, 6, which equals 1 + 2 + 3, and 28, which equals
1 + 2 + 4 + 7 + 14, are perfect numbers. A positive number that is not perfect
is imperfect and is deficient or abundant according to whether the sum of its
positive, proper divisors is smaller or larger than the number itself. Thus, 9,
with proper divisors 1, 3, is deficient; 12, with proper divisors 1, 2, 3, 4,
6, is abundant."
Given a number, determine if it is perfect, abundant, or deficient.