31. 12 sonining bo'luvchilari yig'indisini toping.

First, find all the divisors of 12.

1. 1 divides 12.
2. 2 divides 12.
3. 3 divides 12.
4. 4 divides 12.
5. 6 divides 12.
6. 12 divides 12.

The divisors of 12 are 1, 2, 3, 4, 6, and 12.

Now, sum these divisors:

\( 1 + 2 + 3 + 4 + 6 + 12 = 28 \)

Ответ: 28