What is a whole number that has exactly two distinct factors, 1 and itself?

A whole number that has exactly two distinct factors, namely 1 and itself, is classified as a prime number. This means that a prime number can only be divided evenly by 1 and the number itself, making it unique in how it can be factored. For example, the number 5 can only be divided by 1 and 5 without resulting in a fraction or a decimal, fulfilling the definition of a prime number.

In contrast, composite numbers have more than two distinct factors, which means they can be divided evenly by numbers other than just 1 and themselves. Whole numbers include all non-negative integers, including both prime and composite numbers, while mixed numbers consist of both a whole part and a fractional part. Thus, given the criteria, prime numbers distinctly fit the requirement of only having two factors, which is why the answer is prime number.