Is 1 a prime number?

1. Feb 1, 2004

I've heard ppl say it is and it isn't, so is it a prime number? :P

2. Feb 1, 2004

chroot

Staff Emeritus
3. Feb 1, 2004

yeah, I was kind of leaning towards that it's not a prime number, thanks for confirming :)

4. Feb 2, 2004

mathman

Excluding 1 from the definition of prime number makes it easier to state many theorems in number theory.

For example, every integer can be factored uniquely into a product of (unique) powers of primes. If 1 was called a prime, its exponent could be anything.