What is the smallest prime number?

The smallest prime number is 2. By definition, a prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

In the case of the number 2, it is only divisible by 1 and 2, meeting the criteria for being a prime number. Furthermore, it is the only even prime number; all other even numbers can be divided by 2, which means they have at least three divisors (1, 2, and themselves) and cannot be classified as prime.

This understanding of prime numbers clarifies why the other numbers listed do not qualify. For instance, 1 is not considered prime because it does not meet the minimum requirement of being greater than 1. Meanwhile, 3 and 5 are indeed prime numbers, but they are not the smallest; therefore, they cannot be the correct answer to the question posed. Thus, the correct identification of the smallest prime number is 2.