>>http://studwww.ira.uni-karlsruhe.de/~s_soysal/psychic2.swf
>
>Here is another one.
>
>Take any three-digit number (for example, 452). Repeat the digits twice (for example, 452452).
>
>Now, divide the resulting number by 7. You will have no remainder.
>
>Divide the result by 11. You will have no remainder.
>
>Divide the result by 13. You will have no remainder.
>
>Also, you get the original three-digit number back.

Is there a prime number affect in the proof of this?