An aliquot sum refers to the sum of all the proper divisors of a number, excluding the number itself. For example, the proper divisors of 12 are 1, 2, 3, 4, 6, and their sum is 16. This concept is often used in number theory to classify numbers, such as identifying perfect numbers, which are equal to their aliquot sums. In mathematics, an aliquot part is a divisor of a number that can divide it evenly. The study of aliquot sums helps in understanding the properties of numbers and their relationships. For instance, 6 is a perfect number because its aliquot sum equals the number itself, as the sum of its proper divisors (1, 2, 3) is also 6.