digit/number: Niven's smallest-exponent prime factorization constant c = zeta(3/2)/zeta(3) ≈ 2.1732543125195541382370898404…
This constant plays a role in the bounding of the infinite sum of the smallest exponents in the prime factorizations of the positive natural numbers over the ring of integers; specifically, it is the coefficient of the √(n) term; Niven's bound more fully is given by n + c√(n) + o(√(n)). See also: ni'e'ei