Divisor Sum of 17,296
Jump to navigation
Jump to search
Example of Divisor Sum of Integer
- $\map {\sigma_1} {17 \, 296} = 35 \, 712$
where $\sigma_1$ denotes the divisor sum function.
Proof
- $\ds \map {\sigma_1} n = \prod_{1 \mathop \le i \mathop \le r} \frac {p_i^{k_i + 1} - 1} {p_i - 1}$
where $n = \ds \prod_{1 \mathop \le i \mathop \le r} p_i^{k_i}$ denotes the prime decomposition of $n$.
We have that:
- $17 \, 296 = 2^4 \times 23 \times 47$
Hence:
\(\ds \map {\sigma_1} {17 \, 296}\) | \(=\) | \(\ds \frac {2^5 - 1} {2 - 1} \times \paren {23 + 1} \times \paren {47 + 1}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds \frac {31} 1 \times 24 \times 48\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 31 \times \paren {2^3 \times 3} \times \paren {2^4 \times 3}\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 2^7 \times 3^2 \times 31\) | ||||||||||||
\(\ds \) | \(=\) | \(\ds 35 \, 712\) |
$\blacksquare$