An extensive investigation is reported of the effects of one-particle basis set selection, electron correlation, and molecular vibrations on the static dipole hyperpolarizability of N-2. Our vibrationally averaged values of the mean static polarizability ($) over bar alpha/e(2)a(0)(2)E(H)(-1) = 11.87+/-0.12, the static polarizability anisotropy Delta alpha/e(2)a(0)(2)E(H)(-1) = 4.70+/-0.09, and the mean, static, electronic hyperpolarizability ($) over bar gamma/e(4)a(0)(4)E(H)(-3) = 956+/-50 are in good agreement with experiment. The mean, static, vibronic hyperpolarizability is predicted to be gamma(-upsilon) = 89e(4)a(0)(4)E(H)(-3).