Alright, let's work through 6649 times 6381 step by step
6649 × 6381 = 6381 × (6649)
+ 6381 × 9 which equals 57429
+ 6381 × 40 that is equal 255240
+ 6381 × 600 resulting in 3828600
+ 6381 × 6000 what gives us 38286000

= 42427269
