Alright, let's work through 63924998 times 6780138 step by step
63924998 × 6780138 = 6780138 × (63924998)
+ 6780138 × 8 resulting in 54241104
+ 6780138 × 90 resulting in 610212420
+ 6780138 × 900 that results in 6102124200
+ 6780138 × 4000 which equals 27120552000
+ 6780138 × 20000 that results in 135602760000
+ 6780138 × 900000 what gives us 6102124200000
+ 6780138 × 3000000 yielding 20340414000000
+ 6780138 × 60000000 that equals 406808280000000

= 433420308089724
