Alright, let's work through 77321145 times 99756897 step by step
77321145 × 99756897 = 99756897 × (77321145)
+ 99756897 × 5 that equals 498784485
+ 99756897 × 40 which equals 3990275880
+ 99756897 × 100 yielding 9975689700
+ 99756897 × 1000 that equals 99756897000
+ 99756897 × 20000 producing 1995137940000
+ 99756897 × 300000 producing 29927069100000
+ 99756897 × 7000000 giving us 698298279000000
+ 99756897 × 70000000 which equals 6982982790000000

= 7713317497687065
