File:Abundant_number_Cuisenaire_rods_12.png · Wikimedia Commons · See Wikimedia Commons
abundant number
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number for which the sum of its proper divisors is greater than the number itself
~7 min read
Encyclopedic overview
Demonstration, with Cuisenaire rods, of the abundance of the number 12
In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total of 16. The amount by which the sum exceeds the number is the abundance. The number 12 has an abundance of 4, for example.
Excerpted from Wikipedia’s “abundant number” article, available under the CC BY-SA 4.0 licence.