There's no reason for them, they just exist. It's like asking, what's the reason for the number 7 ? Prime numbers just happen to be numbers you can't divide by other numbers without getting fractions all over the place. Like 7.
Chat with our AI personalities
There is only one even prime number, and that is 2. The reason is that all even numbers greater than 2 have 2 as a factor.
The product of two numbers could be either a composite number or a prime number. If one of those numbers is 1 and the other is a prime number, the result is that prime number. If neither number is 1, the product of the two numbers will be a composite number. If one of those numbers is 1 and the other is not a prime number, the product will not be a prime number. So, in most cases, it will be a composite number.
Any two prime numbers will be relatively prime. Numbers are relatively prime if they do not have any prime factors in common. Prime numbers have only themselves as prime factors, so all prime numbers are relatively prime to the others.
Products of prime numbers are composite numbers.
The opposite of prime numbers are composite numbers.