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Unitary Perfect Number

A number $n$ which is the sum of its Unitary Divisors with the exception of $n$ itself. There are no Odd unitary perfect numbers, and it has been conjectured that there are only a Finite number of Even ones. The first few are 6, 60, 90, 87360, 146361946186458562560000, ... (Sloane's A002827).


Guy, R. K. ``Unitary Perfect Numbers.'' §B3 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 53-59, 1994.

Sloane, N. J. A. Sequence A002827/M4268 in ``An On-Line Version of the Encyclopedia of Integer Sequences.'' and Sloane, N. J. A. and Plouffe, S. The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.

Wall, C. R. ``On the Largest Odd Component of a Unitary Perfect Number.'' Fib. Quart. 25, 312-316, 1987.

© 1996-9 Eric W. Weisstein