Zero is definitively an even number, mathematicians confirm. The formal definition states an even number is any whole number divisible by two with no remainder, a rule zero perfectly satisfies (0 = 2 ...

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory. She reports on topics from maths and history to society and animals. Katie has a PhD in maths, ...

For n a positive integer, let σ(n) denote the sum of the divisors of n. The number n is said to be deficient perfect if σ(n)/n = (2x 1)/x for some x ∊ ℕ. We show that every perfect number has a ...