Alright, let's work through 3953 times 5421 step by step
3953 × 5421 = 5421 × (3953)
+ 5421 × 3 giving us 16263
+ 5421 × 50 which equals 271050
+ 5421 × 900 yielding 4878900
+ 5421 × 3000 that equals 16263000

= 21429213
