What is an example of a prime number?

A prime number is defined as a natural number greater than one that has no positive divisors other than 1 and itself. This means that a prime number cannot be formed by multiplying two smaller natural numbers.

The number 2 is a prime number because its only divisors are 1 and 2. It's also notable as the only even prime number, which makes it unique among prime numbers that are generally odd.

In contrast, the other numbers listed do not meet the criteria for being prime. For example, 4 can be divided evenly by 1, 2, and 4, thus it has divisors other than 1 and itself. The number 6 is divisible by 1, 2, 3, and 6, which also disqualifies it as a prime number. Finally, 9 has divisors of 1, 3, and 9, making it composite rather than prime. Therefore, 2 is the only number among the options that is prime.