Alright, let's work through 81873918 times 47289625 step by step
81873918 × 47289625 = 47289625 × (81873918)
+ 47289625 × 8 that is equal 378317000
+ 47289625 × 10 that is equal 472896250
+ 47289625 × 900 giving us 42560662500
+ 47289625 × 3000 giving us 141868875000
+ 47289625 × 70000 producing 3310273750000
+ 47289625 × 800000 producing 37831700000000
+ 47289625 × 1000000 giving us 47289625000000
+ 47289625 × 80000000 that results in 3783170000000000

= 3871786879500750
