102 is the smallest three digit number with different digits.
smallest 8 digit number with three different digits
999999
102
102.
12345
102,345
1023
Since there are only five different digits, a 6-digit number can only be generated if a digit can be repeated. If digits can be repeated, the smallest 6-digit number is 111111.
19
It is 1,000,002
11223344
555