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So far 47. Euler proved that every even perfect number will be of the form 2p−1(2p−1), where p is prime and 2p−1 is also prime. If 2p−1 is prime it is known as a Mersenne prime. Since 47 Mersenne primes are known, 47 even perfect numbers are known. As for odd perfect numbers, none are known, nor has it been proven yet that there aren't any.

Q: How many perfect numbers are known?

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There is a one-to-one relationship between even perfect numbers and Mersenne primes. It is unknown whether there are any odd perfect numbers.

No, it isn't. In fact, it is not known whether are odd perfect numbers exist. The first perfect numbers are 6, 28, 496, and 8128.

No, there are no known perfect numbers between 1 and 30. The only perfect numbers that have been discovered are 6, 28, 496, and 8128.

There are infinitely many perfect numbers so they cannot all be listed.

No, it is not a perfect number. The first four known perfect numbers are 6, 28, 496 and 8,128.

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No. The only perfect numbers less than 100 are 6 and 28. All known perfect numbers are even - it is unknown whether there are odd perfect numbers.

There is a one-to-one relationship between even perfect numbers and Mersenne primes. It is unknown whether there are any odd perfect numbers.

No, it isn't. In fact, it is not known whether are odd perfect numbers exist. The first perfect numbers are 6, 28, 496, and 8128.

No, there are no known perfect numbers between 1 and 30. The only perfect numbers that have been discovered are 6, 28, 496, and 8128.

There are infinitely many perfect numbers so they cannot all be listed.

If the sum of all a number's factors (factors that are smaller than the number itself) is equal to the number itself, the number is said to be "perfect". For example, the factors of 6 (excluding 6 itself) are 1, 2, and 3; and the sum of these numbers is exactly 6. The smallest perfect numbers are 6, 28, 496, 8128. It isn't known whether the set of perfect numbers is finite or infinite. Also, it isn't known whether there are any odd perfect number; all known perfect numbers are even.

Yes, as has been known since 1588 For a list of all known perfect numbers see the related link.

No, it is not a perfect number. The first four known perfect numbers are 6, 28, 496 and 8,128.

There is no way to determine the amount of perfect numbers there are. The number could be infinite, but this has yet to be proven. It has also yet to be proven if there are any odd perfect numbers.

No, it is not near a perfect number. The first four known perfect numbers are 6, 28, 496 and 8,128.

No, it is not near a perfect number. The first four known perfect numbers are 6, 28, 496 and 8,128.

There are two perfect numbers, 6 and 28, that are less than 100.