Alright, let's work through 1721 times 7790 step by step
1721 × 7790 = 7790 × (1721)
+ 7790 × 1 that results in 7790
+ 7790 × 20 that results in 155800
+ 7790 × 700 producing 5453000
+ 7790 × 1000 that equals 7790000

= 13406590
