Alright, let's work through 67673300 times 81639641 step by step
67673300 × 81639641 = 81639641 × (67673300)
+ 81639641 × 0 producing 0
+ 81639641 × 00 that equals 0
+ 81639641 × 300 that results in 24491892300
+ 81639641 × 3000 which equals 244918923000
+ 81639641 × 70000 that is equal 5714774870000
+ 81639641 × 600000 what gives us 48983784600000
+ 81639641 × 7000000 which equals 571477487000000
+ 81639641 × 60000000 giving us 4898378460000000

= 5524823917285300
