Alright, let's work through 78210690 times 99521413 step by step
78210690 × 99521413 = 99521413 × (78210690)
+ 99521413 × 0 producing 0
+ 99521413 × 90 producing 8956927170
+ 99521413 × 600 that is equal 59712847800
+ 99521413 × 0000 yielding 0
+ 99521413 × 10000 which equals 995214130000
+ 99521413 × 200000 which equals 19904282600000
+ 99521413 × 8000000 that results in 796171304000000
+ 99521413 × 70000000 that results in 6966498910000000

= 7783638380504970
