Divisor Sum of 21,105

Example of Sigma Function of Integer

 * $\sigma \left({21 \, 105}\right) = 42 \, 432$

where $\sigma$ denotes the $\sigma$ function.

Proof
We have that:
 * $21 \, 105 = 3^2 \times 5 \times 7 \times 67$

Hence: