Difference between revisions of "Abundant number"

(Properties)
m (Properties)
Line 15: Line 15:
 
Every positive multiple of an abundant number is an abundant number.
 
Every positive multiple of an abundant number is an abundant number.
  
Every multiple of a perfect number greater than itself is an abundant number.
+
Every multiple of a [[perfect number]] greater than itself is an abundant number.
  
 
==See also==
 
==See also==

Revision as of 20:10, 6 February 2018

An abundant number is a number $n$ for which the sum of its proper divisors is greater than $n$ itself. For example, 12 is abundant because the sum of its proper divisors is 1 + 2 + 3 + 4 + 6 = 16 > 12.

Examples

The first 10 abundant numbers are:

12, 18, 20, 24, 30, 36, 40, 42, 48, 54,...

The first 10 odd abundant numbers are:

945, 1575, 2205, 2835, 3465, 4095, 4725, 5355, 5775, 5985,...

Properties

There are infinitely many abundant numbers.

Every positive multiple of an abundant number is an abundant number.

Every multiple of a perfect number greater than itself is an abundant number.

See also

Perfect number

Deficient number