No problem, we've got 4721 and 4368 to multiply
4721 × 4368 = 4368 × (4721)
+ 4368 × 1 which equals 4368
+ 4368 × 20 that is equal 87360
+ 4368 × 700 what gives us 3057600
+ 4368 × 4000 yielding 17472000

= 20621328
