( 65536 - 1) == 0x0001000100010001 -1 / ( 2^(2^5) - 1) == -1 / (4294967296 - 1) == 0x0000000100000001 Modulo Modular arithmetic with 64-bit modulo by a constant, has applications in Cryptography [5] , Hashing , and with Bitboards in Bit Scanning , Population Count and Congruent Modulo Bitboards for