Alright, let's work through 6404 times 1136 step by step
6404 × 1136 = 1136 × (6404)
+ 1136 × 4 yielding 4544
+ 1136 × 00 which equals 0
+ 1136 × 400 which equals 454400
+ 1136 × 6000 giving us 6816000

= 7274944
