Alright, let's work through 81386538 times 72158688 step by step
81386538 × 72158688 = 72158688 × (81386538)
+ 72158688 × 8 which equals 577269504
+ 72158688 × 30 that results in 2164760640
+ 72158688 × 500 producing 36079344000
+ 72158688 × 6000 producing 432952128000
+ 72158688 × 80000 what gives us 5772695040000
+ 72158688 × 300000 what gives us 21647606400000
+ 72158688 × 1000000 what gives us 72158688000000
+ 72158688 × 80000000 giving us 5772695040000000

= 5872745802942144
