Alright, let's work through 40251399 times 16688825 step by step
40251399 × 16688825 = 16688825 × (40251399)
+ 16688825 × 9 yielding 150199425
+ 16688825 × 90 that is equal 1501994250
+ 16688825 × 300 yielding 5006647500
+ 16688825 × 1000 that equals 16688825000
+ 16688825 × 50000 what gives us 834441250000
+ 16688825 × 200000 that is equal 3337765000000
+ 16688825 × 0000000 that equals 0
+ 16688825 × 40000000 yielding 667553000000000

= 671748553916175
