Alright, let's work through 42720339 times 10502534 step by step
42720339 × 10502534 = 10502534 × (42720339)
+ 10502534 × 9 yielding 94522806
+ 10502534 × 30 which equals 315076020
+ 10502534 × 300 that equals 3150760200
+ 10502534 × 0000 that is equal 0
+ 10502534 × 20000 that results in 210050680000
+ 10502534 × 700000 that is equal 7351773800000
+ 10502534 × 2000000 which equals 21005068000000
+ 10502534 × 40000000 resulting in 420101360000000

= 448671812839026
