Alright, let's work through 2391 times 6431 step by step
2391 × 6431 = 6431 × (2391)
+ 6431 × 1 which equals 6431
+ 6431 × 90 that is equal 578790
+ 6431 × 300 what gives us 1929300
+ 6431 × 2000 that is equal 12862000

= 15376521
