Alright, let's work through 78885689 times 71430655 step by step
78885689 × 71430655 = 71430655 × (78885689)
+ 71430655 × 9 what gives us 642875895
+ 71430655 × 80 resulting in 5714452400
+ 71430655 × 600 yielding 42858393000
+ 71430655 × 5000 producing 357153275000
+ 71430655 × 80000 producing 5714452400000
+ 71430655 × 800000 that equals 57144524000000
+ 71430655 × 8000000 resulting in 571445240000000
+ 71430655 × 70000000 which equals 5000145850000000

= 5634856435396295
