Alright, let's work through 18638997 times 66404136 step by step
18638997 × 66404136 = 66404136 × (18638997)
+ 66404136 × 7 what gives us 464828952
+ 66404136 × 90 giving us 5976372240
+ 66404136 × 900 what gives us 59763722400
+ 66404136 × 8000 resulting in 531233088000
+ 66404136 × 30000 that is equal 1992124080000
+ 66404136 × 600000 producing 39842481600000
+ 66404136 × 8000000 that results in 531233088000000
+ 66404136 × 10000000 giving us 664041360000000

= 1237706491691592
