12980...55649 (34-digits)

This number is a composite.

                                       1298 0742146337 0690713262 4091455649

Probably the last brilliant number of the form 4^n+n^4; 4^55+55^4 = 1298074214633706907132624091455649 = 36028782255016913 * 36028811782917073. Curiously, all semiprimes (except for the first) of the form 4^n+n^4 are also brilliant numbers (4^3+3^4, 4^5+5^4, 4^15+15^4, 4^35+35^4). [Earls]