Divisor Sum of 20,475

Example of Sigma Function of Integer

 * $\map \sigma {20 \, 475} = 45 \, 136$

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

Proof
We have that:
 * $20 \, 475 = 3^2 \times 5^2 \times 7 \times 13$

Hence: