That would be 2 because you can divide both by 2 and get a whole number hope this helps
Factors are the numbers another number can be divided from. example-
8÷4=2, 4 is a factor of 8.
so the factors of 4 are 1,2and 4itself. like this-
4×1=4
1×4=4
2×2=4
answer- 1,2 and 4.