The number 142857 is strange. If you divide 1 by 7 you get .142857142857... and if you divide any other number by 7 you get 142857 somewhere in the string of numbers.

Another strange quality of 142857 is if you multiply it by any number. Here's a chart for the first few numbers.

142857 x 2 = 285714
142857 x 3 = 428571
142857 x 4 = 571428
142857 x 5 = 714285
142857 x 6 = 857142
142857 x 7 = 999999

If you arrange these numbers so each is displaced one number at a time you get the number 451326. Itd doesn't seem like anything but who knows.

142857 x 3 = 428571
142857 x 2 = 285714
142857 x 6 = 857142
142857 x 4 = 571428
142857 x 5 = 714285
142857 x 1 = 142857

If you multiply seven by an increasing number of digits in 142857, then add a number from the 326451 pattern shown above, something interesting happens:

1 x 7 + 3 = 10
14 x 7 + 2 = 100
142 x 7 + 6 = 1000
1428 x 7 + 4 = 10000
14285 x 7 + 5 = 100000
142857 x 7 + 1 = 1000000 

If you multiply 142857 by numbers higher than 7, for example:

142857 x 8 = 1142856

142857 x 259 = 36999963
36 + 999963 = 999999

142857 x 448 = 63999936
63 + 999936 = 999999

If you divide 142857 by nine, you get 15873. If you then take that number and multiply it by seven or a multiple of, this happens:

142857  x  (7  x  1) / 9 = 111111
142857  x  (7  x  2) / 9 = 222222
142857  x  (7  x  3) / 9 = 333333
142857  x  (7  x  4) / 9 = 444444
142857  x  (7  x  5) / 9 = 555555
142857  x  (7  x  6) / 9 = 666666
142857  x  (7  x  7) / 9 = 777777
142857  x  (7  x  8) / 9 = 888888
142857  x  (7  x  9) / 9 = 999999 

Also if you add sections of 142857 up, you get nines.

142 + 857 = 999
285 + 714 = 999
428 + 571 = 999
571 + 428 = 999
714 + 285 = 999
857 + 142 = 999

14 + 28 + 57 = 99
28 + 57 + 14 = 99
42 + 85 + 71 = 99 + 99
57 + 14 + 28 = 99
71 + 42 + 85 = 99 + 99
85 + 71 + 42 = 99 + 99 

1 + 4 + 2 + 8 + 5 + 7 = 9 + 9 + 9

259 is 7 x 37 and 448 is 7 x 64. It's odd how they gave the opposite numbers on the ends. There's more to the numbers 37 and 64.

So what is 142857? It is a result of 1/7. Seven is a very harmonic number and is found in nature and many other places. What the number actually is or means, I'm not sure.