# Definition:Unitary Perfect Number

## Definition

A unitary perfect number is a positive integer which equals the sum of its positive unitary divisors apart from itself.

### Sequence of Unitary Perfect Numbers

The sequence of unitary perfect numbers begins:

$6, 60, 90, 87 \, 360, 146 \, 361 \, 946 \, 186 \, 458 \, 562 \, 560 \, 000, \ldots$

It is not known whether this sequence is complete.