What are the common factors and greatest common factor of 47?

There is neither a greatest common factor nor common factors of a single number, such as 47, because there cannot be any form of common factor without two or more numbers to compare. Common factors are factors that the numbers being compared have in common. The greatest common factor is the largest factor that all the numbers being compared have in common. Thus, since there are not two or more numbers to compare, there are neither common factors nor a greatest common factor.

Examples:

The common factors of 47 and 50 are only 1; the greatest common factor is 1.

The common factors of 47 and 94 are 1 and 47; the greatest common factor is 47.