Alright, let's work through 81394099 times 81697235 step by step
81394099 × 81697235 = 81697235 × (81394099)
+ 81697235 × 9 which equals 735275115
+ 81697235 × 90 which equals 7352751150
+ 81697235 × 000 producing 0
+ 81697235 × 4000 resulting in 326788940000
+ 81697235 × 90000 yielding 7352751150000
+ 81697235 × 300000 which equals 24509170500000
+ 81697235 × 1000000 producing 81697235000000
+ 81697235 × 80000000 producing 6535778800000000

= 6649672833616265
