How to implement One-in-a-Million chance?

I need to develop a function that has a one in a million chance to change one value in my application.

What I first thought was picking a number at the beginning, let's say 10 for example. Then, I call the function that uses Math.Random() to generate a number between 1 and 1000000. I then compared the generated number to the number previously defined (10) and if they are equal the value changes, otherwise it remains the same.

However, I soon realized this did not work due to Math.Random() working with doubles.

Is there any way I can do this? Or is there an alteration to what I've tried that I'm missing?

Thanks, guys!