Mersenne number

9,223,372,036,854,775,807 2,305,843,009,213,693,951 1 3 65535 255 7 147,573,952,589,676,412,927 M127 524287 8191 15 1023 18,446,744,073,709,551,615 31 63 127 2,147,483,647 511