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perfect number

noun, Mathematics
1.
a positive number that is equal to the sum of all positive integers that are submultiples of it, as 6, which is equal to the sum of 1, 2, and 3.
Origin
1350-1400
1350-1400; Middle English
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Examples from the web for perfect number
  • Mathematicians define a perfect number as positive integer that is the sum of it's positive divisors excluding the number itself.
  • Well, where injuries and illnesses are concerned, zero is the perfect number.
British Dictionary definitions for perfect number

perfect number

noun
1.
an integer, such as 28, that is equal to the sum of all its possible factors, excluding itself
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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perfect number in Science
perfect number  
A positive integer that equals the sum of all of its divisors other than itself. An example is 28, whose divisors (not counting itself) are 1, 2, 4, 7, and 14, which added together give 28.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for perfect number

a positive integer that is equal to the sum of its proper divisors. The smallest perfect number is 6, which is the sum of 1, 2, and 3. Other perfect numbers are 28, 496, and 8,128. The discovery of such numbers is lost in prehistory. It is known, however, that the Pythagoreans (founded c. 525 BC) studied perfect numbers for their "mystical" properties.

Learn more about perfect number with a free trial on Britannica.com
Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Word Value for perfect

14
16
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