Perhaps the fact that they are prime numbers!
They only have 2 factors.
the numbers are odd
Prime numbers have two factors. Prime squares have three factors. Square numbers have an odd number of factors but that number varies.
For numbers to be relatively prime, there needs to be two or more numbers to compare their factors.
Prime numbers are prime factors.
All non-zero numbers have factors. Some factors are prime numbers. Prime factors are factors that are prime numbers.
All numbers have factors. Some factors are prime numbers. These are prime factors. A factor string where all the factors are prime numbers is called a prime factorization.
The new number has four factors: 1, the two prime numbers and the new product.
Some factors are prime numbers.
All numbers have factors. Some factors are prime numbers. These are known as prime factors.
All numbers have factors. Some factors are prime numbers. These are known as prime factors.
Prime factors are factors that are also prime numbers.