# What is the greatest common factor of 42 and 72 and 84?

The Greatest Common Factor of 42, 72 and 84 is **6.**

### What is the greatest common factor of 42 and 72?

The greatest common factor of 42 and 72 is 6 Gcf stands for Greatest Common Factor, The gcf of 42 and 72 is the largest positive number that is a factor of both 42 and 72. The positive factors of 42 (the integral divisors of 42) are: 1, 2, 3, 6, 7, 14, 21, and 42. The positive factors of 72 are 1, 2, 3, 4, 6, 8, 9, 12, 18, 36, and 72. Therefore…