Alright, let's work through 66988389 times 38639643 step by step
66988389 × 38639643 = 38639643 × (66988389)
+ 38639643 × 9 what gives us 347756787
+ 38639643 × 80 producing 3091171440
+ 38639643 × 300 resulting in 11591892900
+ 38639643 × 8000 producing 309117144000
+ 38639643 × 80000 giving us 3091171440000
+ 38639643 × 900000 which equals 34775678700000
+ 38639643 × 6000000 which equals 231837858000000
+ 38639643 × 60000000 resulting in 2318378580000000

= 2588407436105127
