Alright, let's work through 81520005 times 86926793 step by step
81520005 × 86926793 = 86926793 × (81520005)
+ 86926793 × 5 that results in 434633965
+ 86926793 × 00 producing 0
+ 86926793 × 000 that results in 0
+ 86926793 × 0000 giving us 0
+ 86926793 × 20000 that results in 1738535860000
+ 86926793 × 500000 resulting in 43463396500000
+ 86926793 × 1000000 that results in 86926793000000
+ 86926793 × 80000000 resulting in 6954143440000000

= 7086272599993965
