So – Why isn’t 1 a Prime Number??
(Inspired by last week’s FoxTrot2 Cartoon!)
Two common mistakes when it comes to primes: 1 is NOT considered a prime, and 2 is prime (the only even prime)!! The fact that 1 is not a prime is often confusing, right? After all, it is technically a number that is ‘divisible only by 1 and itself’ – which is how most people remember and word the definition of prime. So, why isn’t it considered a prime?
Actually, this is not one of those things that ‘came down off the mountain with Moses’. No high authority decreed that 1 shouldn’t be prime – indeed, there was a time (centuries back) when 1 was considered a prime! So, it’s one of those things that has developed into a convention over time, for a variety of reasons, mathematically. One hears lots of ‘explanations’ for this, but for me, there are two main reasons. To see these two reasons, visit 1NotPrime.