Alright, let's work through 81402726 times 66582398 step by step
81402726 × 66582398 = 66582398 × (81402726)
+ 66582398 × 6 resulting in 399494388
+ 66582398 × 20 giving us 1331647960
+ 66582398 × 700 resulting in 46607678600
+ 66582398 × 2000 which equals 133164796000
+ 66582398 × 00000 resulting in 0
+ 66582398 × 400000 that equals 26632959200000
+ 66582398 × 1000000 giving us 66582398000000
+ 66582398 × 80000000 resulting in 5326591840000000

= 5419988700816948
