Originally posted by: dullard
By mathematical definition, 1 is a prime number. However by convention, 1 is excluded from the list of prime numbers.
Hey Dullard, how's it going? I tend to always see you in these threads.
The correct definition of prime number is: A whole number greater than 1 that is divisible by only itself and 1. Most teachers seem to forget to include the first part about being greater than 1. The reason for prime numbers is for prime factorization (factoring something completely into its components).
Every number has a unique prime factorization. i.e. 60's prime factorization is 2*2*3*5.
If 1 was a prime factor, then the factorization could be written as 2*2*3*5*1 or 2*2*3*5*1*1 or 2*2*3*5*1*1*1*1*1*1 or...
Prime numbers are useful for quite a few applications, especially including encryption.