 |
|
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
|
|
almost perfect number
A description sometimes applied to the powers of 2 because the aliquot parts (proper divisors) of 2n sum to 2n - 1. So a power of 2 is a deficient number (one that is less than the sum of its proper divisors), but only just. It isn't known whether there is an odd number n whose divisors (excluding itself) sum to n - 1.
Related categories
• TYPES OF NUMBERS
• MATHEMATICS
Also on this site:
Encyclopedia of Alternative Energy & Sustainable Living
Encyclopedia of History
Transport Concepts & Designs (partner site)