Some integers can be divided evenly into several parts, but some are not. Number N that cannot be divided into any number of parts except for N itself, is called a prime number. Fundamental theorem of arithmetic states that every composite (non-prime) number N can be represented as a product of several lesser prime numbers pi, and the set of these prime numbers is uniquely linked with N. Script on this webpage searches any prime divisors for the given N (a process called factorization) and therefore can be used to determine whether some integer is prime or not.