Alright, let's work through 81880540 times 51203449 step by step
81880540 × 51203449 = 51203449 × (81880540)
+ 51203449 × 0 what gives us 0
+ 51203449 × 40 which equals 2048137960
+ 51203449 × 500 yielding 25601724500
+ 51203449 × 0000 that equals 0
+ 51203449 × 80000 giving us 4096275920000
+ 51203449 × 800000 yielding 40962759200000
+ 51203449 × 1000000 yielding 51203449000000
+ 51203449 × 80000000 producing 4096275920000000

= 4192566053982460
