Is two the only prime number?

no. 2 is the only even Prime number. Prime numbers are numbers that only have two factors; one and itself. E.g. The number 7 only has two factors- 1x7=7. 2 is a factor of all even numbers, therefore no other even numbers are prime. They are composite. 2, however, is a prime number, as it's only factors are itself (2) and 1.