The greatest common divisor, also known as the greatest common factor, refers to the largest common divisor shared by two or more integers. The greatest common divisor of a and b is recorded as (a, b). Similarly, the greatest common divisor of a, b, and c is recorded as (a, b, c). The greatest common divisor of multiple integers also has the same notation. There are many ways to find the greatest common divisor. The most common ones are prime factorization, short division, Euclidean algorithm, and subtraction method. The concept corresponding to the greatest common divisor is the least common multiple. The least common multiple of a and b is recorded as [a, b].