Alright, let's work through 67428587 times 65631894 step by step
67428587 × 65631894 = 65631894 × (67428587)
+ 65631894 × 7 that is equal 459423258
+ 65631894 × 80 giving us 5250551520
+ 65631894 × 500 yielding 32815947000
+ 65631894 × 8000 producing 525055152000
+ 65631894 × 20000 resulting in 1312637880000
+ 65631894 × 400000 producing 26252757600000
+ 65631894 × 7000000 yielding 459423258000000
+ 65631894 × 60000000 yielding 3937913640000000

= 4425465874553778
