Alright, let's work through 81471947 times 64158946 step by step
81471947 × 64158946 = 64158946 × (81471947)
+ 64158946 × 7 giving us 449112622
+ 64158946 × 40 that results in 2566357840
+ 64158946 × 900 what gives us 57743051400
+ 64158946 × 1000 yielding 64158946000
+ 64158946 × 70000 which equals 4491126220000
+ 64158946 × 400000 giving us 25663578400000
+ 64158946 × 1000000 producing 64158946000000
+ 64158946 × 80000000 giving us 5132715680000000

= 5227154248087862
