Alright, let's work through 72123173 times 98635402 step by step
72123173 × 98635402 = 98635402 × (72123173)
+ 98635402 × 3 that results in 295906206
+ 98635402 × 70 that results in 6904478140
+ 98635402 × 100 producing 9863540200
+ 98635402 × 3000 that equals 295906206000
+ 98635402 × 20000 giving us 1972708040000
+ 98635402 × 100000 giving us 9863540200000
+ 98635402 × 2000000 that is equal 197270804000000
+ 98635402 × 70000000 which equals 6904478140000000

= 7113898162370546
