Given that 312 is divisible by 26. It will also be divisible by:
13
For any two numbers x and y, if x is divisible by y, then x is also divisible by each factor of y.
For example, 12 is divisible by 6, and 2 is a factor of 6. So, 12 is also divisible by 2.
Now, factors of 26 = 1, 2, 13, 26
312 is divisible by 26, hence it is also divisible by 13.