Alright, let's work through 81739672 times 81495016 step by step
81739672 × 81495016 = 81495016 × (81739672)
+ 81495016 × 2 what gives us 162990032
+ 81495016 × 70 that results in 5704651120
+ 81495016 × 600 resulting in 48897009600
+ 81495016 × 9000 producing 733455144000
+ 81495016 × 30000 giving us 2444850480000
+ 81495016 × 700000 what gives us 57046511200000
+ 81495016 × 1000000 that equals 81495016000000
+ 81495016 × 80000000 that is equal 6519601280000000

= 6661375877474752
