# Why 1 is not prime [duplicate]

I have been told that there is some interesting mathematics to why the number 1 is not prime. Can someone explain why one is not a prime number?

## marked as duplicate by user147263, Dario, Zubin Mukerjee, Hayden, SurbFeb 6 '15 at 16:37

• By definition, a prime must have only a factor of 1 and itself. Because 1 has no other factor other than itself, it is therefore not prime. – jm324354 Feb 6 '15 at 16:34
• For how long did you search before posting this question? – user147263 Feb 6 '15 at 16:34
• @FamousBlueRaincoat Thanks, I thought this might be a duplicate... – jm324354 Feb 6 '15 at 16:35

• $2$ can be divided by $1$ and $2$
• $11$ can be divided by $1$ and $11$
• $1$ can be divided by $1$ and... $1$ so it is not prime.