What positive whole number is exactly equal to the sum of all its positive proper divisors (factors excluding itself)?
6
The proper divisors of 6 are 1, 2, and 3. 1 + 2 + 3 = 6. (It is the smallest perfect number).
About this riddle
Math riddles hide a calculation inside a short story. Pull out the numbers, work out what is being asked, and watch for a trick such as a unit change.
Difficulty: Medium. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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