No problem, we've got 4787 and 4155 to multiply
4787 × 4155 = 4155 × (4787)
+ 4155 × 7 what gives us 29085
+ 4155 × 80 that equals 332400
+ 4155 × 700 producing 2908500
+ 4155 × 4000 that is equal 16620000

= 19889985
