The prime factorization of 100 is 2^2 x 5^2, or 2 x 2 x 5 x 5. One hundred is considered a composite number because it is a positive integer divisible by at least one positive number other than 1 and 100 (itself).

The factors of 100 are 1, 2, 4, 5, 10, 20, 25, 50 and 100. To find the prime factorization, first take any two of the factors that multiply to make 100. For instance, 25 x 4 = 100. Neither 25 nor four is a prime number, so each must be broken down further. Four equals 2 x 2, and 2 is a prime number. Twenty-five equals 5 x 5, and five is also a prime number. The prime factors are 2 and 5, and each is raised to the second power.