Alright, let's work through 12638505 times 40271978 step by step
12638505 × 40271978 = 40271978 × (12638505)
+ 40271978 × 5 yielding 201359890
+ 40271978 × 00 producing 0
+ 40271978 × 500 which equals 20135989000
+ 40271978 × 8000 yielding 322175824000
+ 40271978 × 30000 what gives us 1208159340000
+ 40271978 × 600000 yielding 24163186800000
+ 40271978 × 2000000 which equals 80543956000000
+ 40271978 × 10000000 resulting in 402719780000000

= 508977595312890
