Alright, let's work through 2139 times 7378 step by step
2139 × 7378 = 7378 × (2139)
+ 7378 × 9 that is equal 66402
+ 7378 × 30 yielding 221340
+ 7378 × 100 producing 737800
+ 7378 × 2000 giving us 14756000

= 15781542
