{{Use shortened footnotes|date=May 2021}}

In [[number theory]], '''Niven's constant''', named after [[Ivan Niven]], is the largest exponent appearing in the [[prime factorization]] of any natural number ''n'' "on average". More precisely, if we define ''H''(1) = 1 and ''H''(''n'') = the largest exponent appearing in the unique prime factorization of a natural number ''n'' > 1, then Niven's constant is given by