Abundant, deficient and perfect number classifications

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These define three classifications of positive integers based on their proper divisors.

Let $P(n)$ be the sum of the proper divisors of n where proper divisors are all positive integers n other than n itself.

If P(n) < n then n is classed as deficient

If P(n) === n then n is classed as perfect

If P(n) > n then n is classed as abundant

Example: 6 has proper divisors of 1, 2, and 3. 1 + 2 + 3 = 6, so 6 is classed as a perfect number.