Alright, let's work through 2599 times 7639 step by step
2599 × 7639 = 7639 × (2599)
+ 7639 × 9 that is equal 68751
+ 7639 × 90 that results in 687510
+ 7639 × 500 yielding 3819500
+ 7639 × 2000 that is equal 15278000

= 19853761
