There are nine factors of 36: 1, 2, 3, 4, 6, 9, 12, 18 and 36. Because the number 36 has more than two factors, it is termed a composite number in mathematics.
Factors are the positive, non-zero whole numbers which, when divided into the number in question, result in a number with no remainder. In the case of 36, for example: 36 ÷ 2 = 8.
A whole number greater than 1 which has only two factors (itself and 1) is termed a prime number. Examples of prime numbers include 3, 5, 7 and 11.
Factoring can also be applied to algebraic expressions. One example of the usefulness of an algebraic factor lies in the polynomial equation x^2 - x - 2 = 0. The factors of x^2 - x - 2 are (x-2) and (x+1), resulting in the simpler equations x-2=0 and x+1=0, yielding the solutions for the original equations, x=2 and x=-1.
The security of data is often ensured using cryptography keys which rely on methods that factor large whole numbers or use factorization. Data transmitted over the Internet is often secured using such public-key cryptography with reliance on advanced factoring methods. Coding also relies on factoring and is a necessary part of digital communication, including telephone, video and satellites.