Alright, let's work through 87850677 times 10399021 step by step
87850677 × 10399021 = 10399021 × (87850677)
+ 10399021 × 7 what gives us 72793147
+ 10399021 × 70 that is equal 727931470
+ 10399021 × 600 that is equal 6239412600
+ 10399021 × 0000 giving us 0
+ 10399021 × 50000 that results in 519951050000
+ 10399021 × 800000 giving us 8319216800000
+ 10399021 × 7000000 that is equal 72793147000000
+ 10399021 × 80000000 that results in 831921680000000

= 913561034987217
