Alright, let's work through 80906401 times 82012907 step by step
80906401 × 82012907 = 82012907 × (80906401)
+ 82012907 × 1 giving us 82012907
+ 82012907 × 00 resulting in 0
+ 82012907 × 400 that results in 32805162800
+ 82012907 × 6000 resulting in 492077442000
+ 82012907 × 00000 that is equal 0
+ 82012907 × 900000 giving us 73811616300000
+ 82012907 × 0000000 producing 0
+ 82012907 × 80000000 which equals 6561032560000000

= 6635369140917707
