An **integer** is a number which can be expressed without the inclusion of values after the decimal point, i.e. it can be expressed as a fraction with denominator 1. Integers are important to the understanding of prime values as primes must have exactly two integer factors, ie they can only be divided by 1 and themselves and result in an integer value. In theory, there are an infinite number of non-integer factors for every number, including prime numbers, but it is the specification of the factor's integer nature which makes prime numbers special.

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