Alright, let's work through 66321401 times 64178894 step by step
66321401 × 64178894 = 64178894 × (66321401)
+ 64178894 × 1 what gives us 64178894
+ 64178894 × 00 resulting in 0
+ 64178894 × 400 producing 25671557600
+ 64178894 × 1000 which equals 64178894000
+ 64178894 × 20000 what gives us 1283577880000
+ 64178894 × 300000 resulting in 19253668200000
+ 64178894 × 6000000 resulting in 385073364000000
+ 64178894 × 60000000 producing 3850733640000000

= 4256434164710494
