142857 Magic
The number 142857 does some amazing tricks; if you multiply it by 2 you get 285714, which is the same digits, rotated 4 positions. If you multiply by 3 you get 428571 (shifted 5 places). And if you multiply it by 7, you get 999999. Interesting, no? In the space below, just type in a positive integer to find out what happens when you multiply 142857 by that number.In case you're interested, 142857 is not the only number that does such interesting stunts and tricks. It's not as much of an oddity as you might think. 142857 is the repeating decimal portion of one seventh (1/7 = .142857142857...).
Are there other fractions whose repeating decimal behaves the same way? You bet there are! But I'm not going to tell you what they are. You'll just have to find them for yourself.