alleryWhich number fails to equal the sum of its proper divisors?
A6
B28
C496
D12
Answer & Solution
Correct answer: D. 12
1. The first perfect numbers are 6, 28, 496 and 8128.
2. The proper divisors of 12 are 1, 2, 3, 4 and 6, which add to 16.
3. 16 differs from 12, so 12 is not perfect.
_Source: Wikipedia, Perfect number, lead section_
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