Alright, let's work through 1638 times 5772 step by step
1638 × 5772 = 5772 × (1638)
+ 5772 × 8 what gives us 46176
+ 5772 × 30 that equals 173160
+ 5772 × 600 which equals 3463200
+ 5772 × 1000 what gives us 5772000

= 9454536
