Definition:Quasiperfect Number/Definition 2

Definition

Let $n \in \Z_{\ge 0}$ be a positive integer.

$n$ is quasiperfect if and only if:

$\map {\sigma_1} n = 2 n + 1$

where $\map {\sigma_1} n$ denotes the divisor sum function of $n$.

Also see

• Equivalence of Definitions of Quasiperfect Number