Mysterious Number



Enter 999999 into your calculator.
Divide the above number by seven.
The result will be a mysterious number!

Throw a die, or randomly pick a number from 1 to 6.
Multiply the result times the mysterious number.
Arrange the digits of the product from lowest to highest from left to right to form a six-digit number.
What is the number?  
It will always be the same number.  Why ?

Created by Martin Gardner.