Alright, let's work through 15781998 times 72601393 step by step
15781998 × 72601393 = 72601393 × (15781998)
+ 72601393 × 8 that is equal 580811144
+ 72601393 × 90 that equals 6534125370
+ 72601393 × 900 that results in 65341253700
+ 72601393 × 1000 that equals 72601393000
+ 72601393 × 80000 yielding 5808111440000
+ 72601393 × 700000 that equals 50820975100000
+ 72601393 × 5000000 that equals 363006965000000
+ 72601393 × 10000000 producing 726013930000000

= 1145795039123214
