5 and 25
Prime numbers have one distinct prime factor.
31 is the only prime factor of 31.
The only prime factor of 16 is 2.
37 is already prime. Its only prime factor is itself.
Since prime numbers only have one prime factor (themselves), they don't have prime factorizations.
Prime numbers.
Prime numbers have one distinct prime factor.
The least common factor of any set of numbers is 1.
Since prime numbers only have one prime factor (themselves), factor trees are unnecessary.
Since all numbers have one as a factor, there is no number with three as its only factor.
Squares (or cubes or more) of prime numbers have one distinct prime factor, but if you're counting them individually, all composite numbers have at least two prime factors.
The only prime factor of 128 is 2.
The only prime factor of 64 is 2.
The only prime factor of 64 is 2.
All prime numbers can be factors.
31 is the only prime factor of 31.
The only prime factor of 16 is 2.