You need at least two numbers to find a GCF.
The Greatest Common Divisor of 21, 189 is 21.
The greatest common factor of 21 and 77 is 7.
The common factors of 21 and 42 are 3, 7 and 21. The greatest common factor (GCF) is 21.
The Greatest Common Factor of 21, 63, 84: 21
The greatest common factor of 21 and 75 is 3.
The greatest common factor of 21 and 162 is 3.
The greatest common factor of 21 and 322 is 7.
The greatest common factor of 21 and 175 is 7.
The Greatest Common Factor of 21, 9 is 3.
The Greatest Common Factor of 14 and 21 is 7.
The greatest common factor of 21 and 56 is 7.
The greatest common factor of 21 and 102 is 3.