What is the smallest prime number?

The smallest prime number is 2 because it is the first number greater than 1 that has exactly two distinct positive divisors: 1 and itself. A prime number, by definition, can only be divided by 1 and the number itself without leaving a remainder. In the case of 2, it is not only a prime number but also the only even prime number. All other even numbers can be divided by 2, giving them at least three divisors, which disqualifies them from being prime. The number 1 is not considered a prime number because it does not meet the criterion of having exactly two distinct positive divisors—it has only one. The numbers 3 and 4 are greater than 2; while 3 is indeed a prime number, it is not the smallest. Thus, 2 is unequivocally the smallest prime number.