No problem, we've got 1644 and 7141 to multiply
1644 × 7141 = 7141 × (1644)
+ 7141 × 4 which equals 28564
+ 7141 × 40 that equals 285640
+ 7141 × 600 which equals 4284600
+ 7141 × 1000 what gives us 7141000

= 11739804
