What is the gcf of 14 and 21?

The greatest common factor (GCF) of 14 and 21 is 7. This is because 7 is the largest number that can evenly divide both 14 and 21 without any remainders. The factors of 14 are 1, 2, 7, and 14, while the factors of 21 are 1, 3, 7, and 21. Since 7 is the largest factor that is common to both numbers, it is the greatest common factor.