1111111111
1,111,111,111
999999
102 is the smallest three digit number with different digits.
The smallest prime number in which all of the digits are also prime is 2.The smallest multi-digit prime number in which all of the digits are also prime is 23.
1.111
12345
111111
111111. Since there are six digits, there must be a repeated digit, so why not repeat all ones to get the smallest one.
13,579 or .13579 . If I'm allowed to repeat digits, then you are 11,111 or .11111 .
123,456 would be the smallest number using all 6 digits. You arrange the numbers from lowest to highest.
The smallest number that when doubled contains all the same digits in a different order.
1023456789