What is the greatest common factor of 54 and 126?

The greatest common factor, (GCF).

Factors of 54 are 1, 2, 3, 6, 9, 18, 27, and 54.

Factors of 126 are 1, 2, 3, 6,9, 18, 14, 21, 42, 63, and 126.

The GCF is 9.