M(77232917) is officially the 50th Mersenne Prime.
M(77232917) was discovered seven and half years ago. Now, thanks to the diligent efforts of many GIMPS volunteers, every smaller Mersenne number has been successfully double-checked. Thus, M(77232917) officially becomes the 50th Mersenne prime.
This is a significant milestone for the GIMPS project. The next Mersenne milestone is not far away, please consider joining this important double-checking effort.
https://www.mersenne.org/report_exponent/?exp_lo=77232917&full=1