amicable number


Definition of amicable number

: either of a pair of numbers each of which equals the sum of the different exact divisors of the other excluding the number itself

Note: 220 and 284 are examples of amicable numbers. The factors of 220 are 1, 2, 4, 5, 10, 11, 20, 22, 44, 55, and 110, which sum to 284, while the factors of 284 are 1, 2, 4, 71, and 142, which sum to 220.

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First Known Use of amicable number

circa 1763, in the meaning defined above

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The first known use of amicable number was circa 1763

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Cite this Entry

“Amicable number.” Dictionary, Merriam-Webster, Accessed 26 May. 2020.

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