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In number theory, a perfect number is a positive integer that is equal to the sum of its positive proper divisors, that is, divisors excluding the number itself. For instance, 6 has proper divisors 1, 2, and 3, and 1 + 2 + 3 = 6, so 6 is a perfect number. The next perfect number is 28, because 28 has proper divisors 1, 2, 4, 7, 14, and 1 + 2 + 4 + 7 + 14…
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perfect displaystyle number numbers prime even odd divisors -1 form sum also 28 proper 10 known every mersenne called 8128
| Subject | Predicate | Object | Confidence | Src |
|---|---|---|---|---|
| Perfect number | is a | positive integer that is equal to the sum of its positive proper divisors | 0.90 | text |
| Perfect number | is a | number that is half the sum of all of its positive divisors | 0.90 | text |
| Perfect number | is a | manuscript written between 1456 and 1461 by an unknown mathematician | 0.90 | text |
| Perfect number | is a | pernicious number.Every even perfect number is also a practical number | 0.90 | text |
| Perfect number | is a | Ore's harmonic number.The even perfect numbers are not trapezoidal numbers | 0.90 | text |
| Perfect number | is a | fixed point of the restricted divisor function s | 0.90 | text |
| Perfect number | related to Even perfect numbers | Euclid | 0.60 | section |
| Perfect number | related to Even perfect numbers | Elements | 0.60 | section |
| Perfect number | related to Even perfect numbers | Book IX | 0.60 | section |
| Perfect number | related to Even perfect numbers | Proposition | 0.60 | section |
| Perfect number | related to Even perfect numbers | For | 0.60 | section |
| Perfect number | related to External links | Perfect | 0.60 | section |
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