Alright, let's work through 81891423 times 41264428 step by step
81891423 × 41264428 = 41264428 × (81891423)
+ 41264428 × 3 that is equal 123793284
+ 41264428 × 20 yielding 825288560
+ 41264428 × 400 yielding 16505771200
+ 41264428 × 1000 which equals 41264428000
+ 41264428 × 90000 resulting in 3713798520000
+ 41264428 × 800000 that equals 33011542400000
+ 41264428 × 1000000 that is equal 41264428000000
+ 41264428 × 80000000 producing 3301154240000000

= 3379202728201044
