Divisor Sum of 87

Example of Divisor Sum of Non-Square Semiprime

 * $\map {\sigma_1} {87} = 120$

where $\sigma_1$ denotes the divisor sum function.

Proof
We have that:
 * $87 = 3 \times 29$

and so by definition is a semiprime whose prime factors are distinct.

Hence: