No problem, we've got 2541 and 7815 to multiply
2541 × 7815 = 7815 × (2541)
+ 7815 × 1 yielding 7815
+ 7815 × 40 yielding 312600
+ 7815 × 500 what gives us 3907500
+ 7815 × 2000 what gives us 15630000

= 19857915
