Alright, let's work through 1580 times 6457 step by step
1580 × 6457 = 6457 × (1580)
+ 6457 × 0 yielding 0
+ 6457 × 80 what gives us 516560
+ 6457 × 500 which equals 3228500
+ 6457 × 1000 yielding 6457000

= 10202060
