Divisor Sum of 672
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Example of Divisor Sum of Integer
- $\map {\sigma_1} {672} = 2016$
where $\sigma_1$ denotes the divisor sum function.
Proof
We have that:
- $672 = 2^5 \times 3 \times 7$
Hence:
\(\ds \map {\sigma_1} {672}\) | \(=\) | \(\ds \frac {2^6 - 1} {2 - 1} \times \paren {3 + 1} \times \paren {7 + 1}\) | Divisor Sum of Integer | |||||||||||
\(\ds \) | \(=\) | \(\ds \frac {63} 1 \times 4 \times 8\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds \paren {3^2 \times 7} \times 2^2 \times 2^3\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2^5 \times 3^2 \times 7\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2016\) |
$\blacksquare$