Alright, let's work through 6460421 times 98851440 step by step
6460421 × 98851440 = 98851440 × (6460421)
+ 98851440 × 1 giving us 98851440
+ 98851440 × 20 that is equal 1977028800
+ 98851440 × 400 producing 39540576000
+ 98851440 × 0000 giving us 0
+ 98851440 × 60000 that results in 5931086400000
+ 98851440 × 400000 resulting in 39540576000000
+ 98851440 × 6000000 giving us 593108640000000

= 638621918856240
