Superabundant Number/Examples/4

Example of Superabundant Number

The abundancy index of $4$ is:

$\dfrac {\map {\sigma_1} 4} 4 = \dfrac 7 4 = 1 \cdotp 75$

Proof

\(\ds \map {\sigma_1} 4\)

\(=\)

\(\ds 7\)

$\sigma_1$ of $4$

\(\ds \leadsto \ \ \)

\(\ds \dfrac {\map {\sigma_1} 4} 4\)

\(=\)

\(\ds \dfrac 7 4\)

\(\ds \)

\(=\)

\(\ds 1 \cdotp 75\)

$\blacksquare$