Alright, let's work through 63903453 times 16801321 step by step
63903453 × 16801321 = 16801321 × (63903453)
+ 16801321 × 3 giving us 50403963
+ 16801321 × 50 that results in 840066050
+ 16801321 × 400 that equals 6720528400
+ 16801321 × 3000 producing 50403963000
+ 16801321 × 00000 what gives us 0
+ 16801321 × 900000 resulting in 15121188900000
+ 16801321 × 3000000 that is equal 50403963000000
+ 16801321 × 60000000 that equals 1008079260000000

= 1073662426861413
