A number which is an integer multiple of the sum of its unitary divisors is called a unitary -multiperfect number. There are no odd unitary multiperfect numbers.
Unitary Multiperfect Number
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References
Guy, R. K. "Unitary Perfect Numbers." §B3 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 53-59, 1994.Suryanarayana, D. "The Number of Bi-Unitary Divisors of an Integer." The Theory of Arithmetic Functions (Proc. Conf., Western Michigan Univ., Kalamazoo, Mich., 1971. New York: Springer-Verlag, pp. 273-282, 1972.Suryanarayana, D. and Rao, R. S. R. C. "The Number of Bi-Unitary Divisors of an Integer. II." J. Indian Math. Soc. 39, 261-280, 1975.Wall, C. R. "Bi-Unitary Perfect Numbers." Proc. Amer. Math. Soc. 33, 39-42, 1972.Referenced on Wolfram|Alpha
Unitary Multiperfect NumberCite this as:
Weisstein, Eric W. "Unitary Multiperfect Number." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/UnitaryMultiperfectNumber.html