Zagadachnoe number Bashny.Net

Here is a mysterious number which is associated with many stories. Let's start with the multiplication and see what happens.
142 857 × 1 = 142,857
142,857 × 2 = 285714
142 857 × 3 = 428,571
142 857 × 4 = 571428
142857 × 5 = 714285
142 857 × 6 = 857142
The same figures change their position, moving like a ribbon.
A 142,857 × 7?
999 999!
If you add 142 and 857, you get 999.
14 28 57 = 99
142,857 square gives 20408122449; 20 408 and 122 449 - two parts of this number. If you add them up, it will ... 142,857.