What is the smallest perfect number?

A perfect number is defined as a positive integer that is equal to the sum of its proper divisors, excluding itself. To identify the smallest perfect number, we should look for a number that meets this definition.

Starting with the number six, its divisors are: 1, 2, and 3. When we add these proper divisors together, we have:

1 + 2 + 3 = 6

Since the sum of the proper divisors equals the number itself, six qualifies as a perfect number.

On the other hand, the other choices do not qualify as perfect numbers. The number two, for example, has proper divisors of only 1, which sums to 1, not equal to 2. The number four has proper divisors of 1 and 2, which sum to 3, while the number eight has proper divisors of 1, 2, and 4, summing to 7. Neither of these matches their respective numbers, confirming they are not perfect.

Thus, six stands as the smallest perfect number, fulfilling the criteria perfectly and making it the correct answer.