Alright, let's work through 8404 times 6404 step by step
8404 × 6404 = 6404 × (8404)
+ 6404 × 4 that results in 25616
+ 6404 × 00 what gives us 0
+ 6404 × 400 yielding 2561600
+ 6404 × 8000 yielding 51232000

= 53819216
