62429...92441 (40-digits)

This number is a prime.

                                 6242950767 9048925471 1074531320 3633592441

6242950767904892547110745313203633592441 = 8888888888^4 + 8888888888^3 + 8888888888^2 + 8888888888^1 + 8888888888^0. [Nwamba]