Question

is the only even prime number.

Answer 1

Prime numbers are those numbers that have only 2 factors, 1 and the number itself.
1 is neither prime nor composite. It is also an odd number.
4 is an even number whose factors are 1, 2, and 4.
2 is an even number whose factors are only 1 and 2.
2 is the only prime number that is even. All other even numbers have a factor 2.