In number theory, a perfect number is a positive integer that is equal to the sum of its proper positive divisors, that is, the sum of its positive divisors excluding the number itself (also known as its aliquot sum). Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself) i.e. σ1(n) = 2n.
Read more about Perfect Number: Examples, Discovery, Even Perfect Numbers, Odd Perfect Numbers, Minor Results, Related Concepts
Famous quotes containing the words perfect and/or number:
“The novel is a perfect medium for revealing to us the changing rainbow of our living relationships. The novel can help us to live, as nothing else can: no didactic Scripture, anyhow. If the novelist keeps his thumb out of the pan.”
—D.H. (David Herbert)
“Black lady,
what will I do
without your two flowers?
I have inhabited you, number by number.
I have pushed you in and out like a needle.”
—Anne Sexton (1928–1974)