Alright, let's work through 5407 times 1071 step by step
5407 × 1071 = 1071 × (5407)
+ 1071 × 7 yielding 7497
+ 1071 × 00 giving us 0
+ 1071 × 400 which equals 428400
+ 1071 × 5000 yielding 5355000

= 5790897
