Divisor Sum of 497
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Example of Divisor Sum of Integer
- $\map {\sigma_1} {497} = 576$
where $\sigma_1$ denotes the divisor sum function.
Proof
From Divisor Sum of Integer: Corollary
- $\ds \map {\sigma_1} n = \prod_{1 \mathop \le i \mathop \le r} \frac {p_i^{k_i + 1} - 1} {p_i - 1}$
where $n = \ds \prod_{1 \mathop \le i \mathop \le r} p_i^{k_i}$ denotes the prime decomposition of $n$.
We have that:
- $497 = 7 \times 71$
Hence:
\(\ds \map {\sigma_1} {497}\) | \(=\) | \(\ds \paren {7 + 1} \paren {71 + 1}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 8 \times 72\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2^3 \times \paren {2^3 \times 3^2}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2^6 \times 3^2\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds \paren {2^3 \times 3}^2\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 24^2\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 576\) |
$\blacksquare$