I am the only two-digit number that equals the sum of all my proper positive divisors (excluding myself). What number am I?
28
This describes a perfect number. The proper positive divisors of 28 are 1, 2, 4, 7, and 14. Their sum is 1 + 2 + 4 + 7 + 14 = 28. It is the only two-digit 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: Easy. More like this: Math riddles with answers or try Target 24 for a different kind of puzzle.
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