Alright, let's work through 42123897 times 86056469 step by step
42123897 × 86056469 = 86056469 × (42123897)
+ 86056469 × 7 which equals 602395283
+ 86056469 × 90 which equals 7745082210
+ 86056469 × 800 yielding 68845175200
+ 86056469 × 3000 resulting in 258169407000
+ 86056469 × 20000 which equals 1721129380000
+ 86056469 × 100000 producing 8605646900000
+ 86056469 × 2000000 that is equal 172112938000000
+ 86056469 × 40000000 yielding 3442258760000000

= 3625033836339693
