Alright, let's work through 20639455 times 18031941 step by step
20639455 × 18031941 = 18031941 × (20639455)
+ 18031941 × 5 producing 90159705
+ 18031941 × 50 producing 901597050
+ 18031941 × 400 that equals 7212776400
+ 18031941 × 9000 producing 162287469000
+ 18031941 × 30000 producing 540958230000
+ 18031941 × 600000 that is equal 10819164600000
+ 18031941 × 0000000 resulting in 0
+ 18031941 × 20000000 yielding 360638820000000

= 372169434832155
