Alright, let's work through 6621 times 3123 step by step
6621 × 3123 = 3123 × (6621)
+ 3123 × 1 which equals 3123
+ 3123 × 20 resulting in 62460
+ 3123 × 600 giving us 1873800
+ 3123 × 6000 resulting in 18738000

= 20677383
