# Category:Definitions/Abundancy

This category contains definitions related to Abundancy.
Related results can be found in Category:Abundancy.

Let $n$ be a positive integer.

Let $\map \sigma n$ be the sigma function of $n$.

That is, let $\map \sigma n$ be the sum of all positive divisors of $n$.

Then the abundancy index of $n$ is defined as $\dfrac {\map \sigma n} n$.

## Subcategories

This category has the following 13 subcategories, out of 13 total.

## Pages in category "Definitions/Abundancy"

The following 10 pages are in this category, out of 10 total.