Alright, let's work through 6578 times 6416 step by step
6578 × 6416 = 6416 × (6578)
+ 6416 × 8 that equals 51328
+ 6416 × 70 producing 449120
+ 6416 × 500 resulting in 3208000
+ 6416 × 6000 yielding 38496000

= 42204448
