(4) A number in which the sum of all its proper factors is equal to the number itself. Example: 6 is a perfect number because when you add its proper factors the answer is equal to 6: 1 + 2 + 3 = 6.

A number whose proper factors sum up to the number itself. For example, the proper factors of 6 are 1, 2, and 3, which sum to 6.

an integer greater than zero whose factors less than the number all add up to the number (i

an integer n such that the sum of the proper divisors of n is equal to n

an integer such that the sum of its own divisors is twice the number

an integer that equals the sum of its proper divisors

a number (an integer ) for which the sum of its proper factors (divisors) is equal to the number itself

a number that all of its factors excluding itself add up to the number

a number that is equal to the sum of all of its (positive) divisors, excluding itself

a number that is equal to the sum of its proper factors -- that is, all the positive numbers less than the number itself, that divide evenly into the number

a number that is numerically equal to the sum of its divisors, i

a number which has all its integer factors added together to result in the source number

a number whose divisors sum to twice itself

a number whose factors, including the number itself, sum up to twice the number

a number who's factors sum up to the number itself

a number with factors which, when added together, add up to te number

a positive integer for which the sum of the positive divisors less than the number is equal to the number itself

a positive integer that has the property that it is equal to the sum of its proper divisors

A number for which the sum of all the proper factors is equal to the number itself. For example, 6 is a perfect number because the sum of its proper factor is 1 + 2 + 3 = 6. See also abundant numbers, deficient numbers, and proper factor.

A number that is the sum of its factors.EG 6=1+2+3

An integer that is equal to the sum of its divisors, excluding itself.

In mathematics, a perfect number is defined as an integer which is the sum of its proper positive divisors, that is, the sum of the positive divisors not including the number. Equivalently, a perfect number is a number that is half the sum of all of its positive divisors, or σ(n) = 2 n.