Alright, let's work through 78638555 times 82971071 step by step
78638555 × 82971071 = 82971071 × (78638555)
+ 82971071 × 5 giving us 414855355
+ 82971071 × 50 giving us 4148553550
+ 82971071 × 500 that equals 41485535500
+ 82971071 × 8000 which equals 663768568000
+ 82971071 × 30000 which equals 2489132130000
+ 82971071 × 600000 producing 49782642600000
+ 82971071 × 8000000 which equals 663768568000000
+ 82971071 × 70000000 giving us 5807974970000000

= 6524725130242405
