Alright, let's work through 80109648 times 54121939 step by step
80109648 × 54121939 = 54121939 × (80109648)
+ 54121939 × 8 giving us 432975512
+ 54121939 × 40 giving us 2164877560
+ 54121939 × 600 yielding 32473163400
+ 54121939 × 9000 that is equal 487097451000
+ 54121939 × 00000 producing 0
+ 54121939 × 100000 that is equal 5412193900000
+ 54121939 × 0000000 which equals 0
+ 54121939 × 80000000 which equals 4329755120000000

= 4335689482367472
