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An almost perfect number is a natural number n such that the sum of all divisors of n is equal to 2n - 1.
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What numbers are almost perfect numbers?
Almost perfect numbers refer to numbers whereσ(x) = 2x - 1, where σ is the sum of divisors function. Any number in the form 2n is almost perfect becauseσ(2n) = 1 + 2 + 4 + ... + 2n = 2n+1-1 = 2(2n) - 1.It is unknown whether any other almost perfect numbers exist.
What are all perfect numbers?
There are infinitely many perfect numbers so they cannot all be listed.
What are 2 almost perfect numbers between 5 and 20?
Perfect numbers are numbers where all the factors add to that number. For example 6's factors are 1,2, and 3 and 1+2+3=6. Therefore the next perfect number isn't until 28 which is 1,2, 4, 7, 14 where 1+2+4+7+14= 28 An almost perfect number is a number which, when adding all of its proper divisors (all divisors except himself), gives you one less, or one more then the number itlself. Up to now all known almost perfect numbers are 2^n. So to answer your question, the 2 almost perfect numbers between 5 and 20 are 8 and 16. Divisors of 8: 1,2,4 -----> 1+2+4=7 Divisors of 16: 1,2,4,8 -----> 1+2+4+8=15
Are no perfect squares whole numbers?
By definition, ALL perfect squares are whole numbers!
Is 32 an almost perfect number?
Yes. The only known almost perfect numbers are the powers of 2. 32 = 2^5 is an almost perfect number. It has not yet been proved whether {x: x = 2^n for n in N} = {x: x is an almost perfect number}.
How much numbers do pi got?
For almost all mathmatics and physics uses, pi is writen as 3.1417. But it is actually an irrational number, and has no perfect answer.
Is 31 a perfect number?
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.
What are near perfect numbers?
They are numbers that are NEAR PERFECT. a near perfect number is when its factors (exept the actual number) are added up and ALMOST equal the number ex. 16x1/2x8/4x4/ so its factors are 1,2,4,8 and 16 so add them ( exept the actual number) 1+2+4+8=15 so its NEAR PERFECT and a perfect number is a number that all its factors equal to its number ex. 6-1,2,3,6 are its factors all together-1+2+3=6 those are NEAR PERFECT and PERFECT numbers
What are all numbers with an even amount of factors?
All compound numbers that are not perfect squares.
What are all the perfect numbers less than 100?
The perfect numbers less than 100 are 6 and 28.
Can you write every integer as the sum of two nonzero perfect squares?
No.First of all, you can't write negative numbers as sums of perfect squares at all - since all perfect squares are positive.Second, for natural numbers (1, 2, 3...) you may need up to 4 perfect squares: http://en.wikipedia.org/wiki/Lagrange's_four-square_theoremNo.First of all, you can't write negative numbers as sums of perfect squares at all - since all perfect squares are positive.Second, for natural numbers (1, 2, 3...) you may need up to 4 perfect squares: http://en.wikipedia.org/wiki/Lagrange's_four-square_theoremNo.First of all, you can't write negative numbers as sums of perfect squares at all - since all perfect squares are positive.Second, for natural numbers (1, 2, 3...) you may need up to 4 perfect squares: http://en.wikipedia.org/wiki/Lagrange's_four-square_theoremNo.First of all, you can't write negative numbers as sums of perfect squares at all - since all perfect squares are positive.Second, for natural numbers (1, 2, 3...) you may need up to 4 perfect squares: http://en.wikipedia.org/wiki/Lagrange's_four-square_theorem
Are perfect squares all rational numbers?
Yes.
