It is not possible to give a sensible answer to this question. The greatest common factor (GCF) refers to a factor that is COMMON to two or more numbers. You have only one number in the question!
It is: 3
The greatest common factor of 15 and 18 is three.
The greatest common factor of the numbers 32 and 22 is 2.
48 and 84's highest common factor is 12.
3
what is the greastest common factor of 32
14
7 
3 is.
5
5
8
34
1
7
It is: 6
It is: 16