If you'll accept a decimal, then it's .0123456789
If you want whole numbers only, and you'll accept a leading zero, then it's 0,123,456,789.
If not, then it's 1,023,456,789.
1,234,567
5
5
none
0132 or 1234 0123 or without 0 at front = 1023
The smallest number with no digits repeated would either be zero or one, depending on the set of numbers you want to choose from.
102
0123456789
10234567
123456.
1023456789
1234567