How about 256
102 is the smallest three digit number with different digits.
000
smallest 8 digit number with three different digits
638
102
102
100,002.
10002
All five digit numbers have three digits. The smallest five digit whole number is 10,000
There are only two smaller 3-digit numbers and both of them have repeated digits.
The number formed by the last three digits have to be divisible by 8.
964.