Alright, let's work through 99727709 times 15254013 step by step
99727709 × 15254013 = 15254013 × (99727709)
+ 15254013 × 9 that is equal 137286117
+ 15254013 × 00 that is equal 0
+ 15254013 × 700 that equals 10677809100
+ 15254013 × 7000 yielding 106778091000
+ 15254013 × 20000 that results in 305080260000
+ 15254013 × 700000 that results in 10677809100000
+ 15254013 × 9000000 that results in 137286117000000
+ 15254013 × 90000000 which equals 1372861170000000

= 1521247769546217
