Alright, let's work through 1721 times 7801 step by step
1721 × 7801 = 7801 × (1721)
+ 7801 × 1 that is equal 7801
+ 7801 × 20 which equals 156020
+ 7801 × 700 giving us 5460700
+ 7801 × 1000 producing 7801000

= 13425521
