sociable number

Noun

 * 1)  Any of a sequence of numbers having the property that the sum of the divisors of each, excluding itself, is equal to the next number in the sequence; in the case of the last number of the sequence, the sum of the divisors, excluding that number, is equal to the first number of the sequence.
 * The numbers in the sequence <1264460, 1547860, 1727636, 1305184> are sociable numbers.