# Math Help - multiplicative

1. ## Compute sigma(n)

See attachment. Thanks

2. 1) $\sigma (p^k) = \frac{p^{k+1} - 1}{p-1}$ where $p$ is prime.
2) $\sigma (nm) = \sigma( n ) \sigma (m)$ for relatively prime positive integers.

With that you can solve the problem.