What is the smallest prime number?

The smallest prime number is 2. A prime number is defined as a natural number greater than 1 that has no positive divisors other than 1 and itself. The number 2 fits this definition perfectly, as its only divisors are 1 and 2. Additionally, 2 is unique as the only even prime number; all other even numbers can be divided by 2, disqualifying them from being prime.

In contrast, the number 1 is not considered a prime number because it does not meet the requirement of having two distinct positive divisors; it only has one. The numbers 3 and 5 are indeed prime, but they are larger than 2, making them not the smallest.