The factors of 91 are 1, 7, 13, 91. For them to be common, they need to be compared to another set of factors.
You need at least two numbers to find a GCF.
1 is the highest common factor of 91 and 251.
The highest common factor is 7.
The highest common factor of the numbers 28, 84 and 91 is 7.
The highest common factor of the numbers 91, 156 and 169 is 13.
The highest factor of any positive integer is the integer itself. The highest common factor of 91 and 203 is 7.
The Greatest Common Factor (GCF) is: 13
13
It is 7
It is: 13
91
7
If you mean the highest common factor then it is 7