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A number 
 is called an 
-perfect number if 
, where 
 is the Sum of the
e-Divisor of 
.  If 
 is Squarefree, then 
.  As a result, if 
is 
-perfect and 
 is Squarefree with 
, then 
 is 
-perfect.  There are no Odd 
-perfect
numbers.
See also e-Divisor
References
Guy, R. K.  ``Exponential-Perfect Numbers.''  §B17 in
  Unsolved Problems in Number Theory, 2nd ed.  New York: Springer-Verlag, p. 73, 1994.
 
Subbarao, M. V. and Suryanarayan, D.  ``Exponential Perfect and Unitary Perfect Numbers.''
  Not. Amer. Math. Soc. 18, 798, 1971.