Amicable Numbers(redirected from Amicable number)
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amicable numbers[′am·ə·kə·bəl ′nəm·bərz]
a pair of natural numbers, each of which is equal to the sum of all the exact divisors of the other, that is, divisors that are different from the number itself. The amicable numbers 284 and 220, whose corresponding sums of divisors are 1 + 2 + 4 + 5 + 10 + 11 + 20 + 22 + 44 + 55 + 110 = 284 and 1 + 2 + 4 + 71 + 142 = 220, were already known in antiquity. Assigning a mystical meaning to the properties of numbers, the Pythagoreans attached great importance to amicable numbers. L. Euler found approximately 60 pairs of amicable numbers. The use of computers has made it possible to find several hundred more pairs of amicable numbers. These numbers are primarily of historical interest.