A number theoretic function is a function whose domain is the set of positive integers.
Number Theoretic Function
See also
Arithmetic Function, Integer Function, Multiplicative Number Theoretic FunctionRelated Wolfram sites
http://functions.wolfram.com/NumberTheoryFunctions/Explore with Wolfram|Alpha
References
Wilf, H. Generatingfunctionology, 2nd ed. New York: Academic Press, p. 58, 1994.Referenced on Wolfram|Alpha
Number Theoretic FunctionCite this as:
Weisstein, Eric W. "Number Theoretic Function." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/NumberTheoreticFunction.html