No problem, we've got 6439 and 1607 to multiply
6439 × 1607 = 1607 × (6439)
+ 1607 × 9 that results in 14463
+ 1607 × 30 that is equal 48210
+ 1607 × 400 that is equal 642800
+ 1607 × 6000 producing 9642000

= 10347473
