Alright, let's work through 90401708 times 20520097 step by step
90401708 × 20520097 = 20520097 × (90401708)
+ 20520097 × 8 giving us 164160776
+ 20520097 × 00 which equals 0
+ 20520097 × 700 that equals 14364067900
+ 20520097 × 1000 producing 20520097000
+ 20520097 × 00000 that equals 0
+ 20520097 × 400000 that results in 8208038800000
+ 20520097 × 0000000 which equals 0
+ 20520097 × 90000000 that is equal 1846808730000000

= 1855051817125676
