# perfect number

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## perfect number

n.
A positive integer that is equal to the sum of its positive integral factors, including 1 but excluding itself.

## perfect number

n
(Mathematics) an integer, such as 28, that is equal to the sum of all its possible factors, excluding itself
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014

## per′fect num′ber

n.
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.
[1350–1400]

## per·fect number

(pûr′fĭkt)
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.
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References in periodicals archive ?
However, it is not known whether the number of perfect numbers is infinite.
Also part of the selection will be Qatari plate numbers 97400 and 1218, the "perfect numbers to display for National Day", the statement notes.
They discuss topics like what prime numbers are, division and multiplication, congruences, Euler's theorem, testing for primality and factorization, Fermat numbers, perfect numbers, the Newton binomial formula, money and primes, cryptography, new numbers and functions, primes in arithmetic progression, and sequences, with examples, some proofs, and biographical notes about key mathematicians.
Many times we go to the academy to bring some young boys to have a group with the perfect numbers to train.
And even if the homework does not involve the five times table, there is plenty of hand-holding for nervous adults called upon to help with trigonometry, perfect numbers and the golden ratio.
We had a mild winter with no big spring freezes, and the quality looks good." He reported that Chardonnay had close to perfect numbers for the region, with 23[degrees] Brix, total acidity between 5 and 7 grams per liter and pH at 3.4 or 3.5.
Much interest was expressed in the socalled perfect numbers such as 6, 28, 496, and 8128; numbers whose divisors add up to the number.
They relate to mainstream and more mathematical topics appealing to mathematicians and enthusiasts, including whether bees can count, the significance of the number 13, Sudoku puzzles, perfect numbers, pi, the Pythagorean theorem, the body mass index, and figures like Paul Erdos, Gian-Carlo Rota, Persi Diaconis, Daniel Biss, and Caroline Lasser.
I have read that Mark Wallinger's art exhibition at the Baltic is themed on Super Perfect Numbers. What are Super Perfect Numbers?
The answer is yes, and they are called perfect numbers, but they are very rare.
Coming in seventh was Anirudh Prabhu, 17, of West Lafayette, Ind., who received \$25,000 for demonstrating that odd perfect numbers, which equal the sum of every number they can be cleanly divided by, have a lower limit.
"I hope he gets there in this match, it would make it the perfect numbers game," said Zaheer Khan.

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