Can you create a 10-digit number, where the first digit is how many zeros in the number, the second digit is how many 1s in the number etc. until the tenth digit which is how many 9s in the number?
Can it be 0000000000?
Can it be 9000000000?
Source: Richard Wiseman.
One answer, slightly obfuscated, is 2³ * 5³ * 7 * 887143