Alright, let's work through 2604 times 2604 step by step
2604 × 2604 = 2604 × (2604)
+ 2604 × 4 what gives us 10416
+ 2604 × 00 that results in 0
+ 2604 × 600 yielding 1562400
+ 2604 × 2000 which equals 5208000

= 6780816
