perfect number
noun Mathematics.
a positive number that is equal to the sum of all positive integers that are submultiples of it, as 6, which is equal to the sum of 1, 2, and 3.
Compare
abundant number,
deficient number.
Origin of perfect number
Middle English word dating back to 1350–1400
Words nearby perfect number
British Dictionary definitions for perfect number
perfect number
noun
an integer, such as 28, that is equal to the sum of all its possible factors, excluding itself
Scientific definitions for perfect number
perfect number
A positive integer that equals the sum of all of its divisors other than itself. An example is 28, whose divisors (not counting itself) are 1, 2, 4, 7, and 14, which added together give 28.