Alright, let's work through 8199 times 9009 step by step
8199 × 9009 = 9009 × (8199)
+ 9009 × 9 producing 81081
+ 9009 × 90 yielding 810810
+ 9009 × 100 giving us 900900
+ 9009 × 8000 producing 72072000

= 73864791
