is an infinary divisor of (with ) if . This generalizes the concept of the k-ary Divisor.
See also Infinary Perfect Number, k-ary Divisor
References
Cohen, G. L. ``On an Integer's Infinary Divisors.'' Math. Comput. 54, 395-411, 1990.
Cohen, G. and Hagis, P. ``Arithmetic Functions Associated with the Infinary Divisors of an Integer.''
Internat. J. Math. Math. Sci. 16, 373-383, 1993.
Guy, R. K. Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, p. 54, 1994.