76912895956636885

This number is a composite.

On September 16, 1998, Tony Forbes found the 1004-digit prime quadruplets: 76912895956636885 * (2³²⁷⁹ - 2¹⁰⁹³) - 6 * 2¹⁰⁹³ {-7, -5, -1, +1}. This is the first known titanic quadruple.