Let's see how good /prog/ really is

Can you find the smallest number that fulfills the following criteria?

1. It can only contain digits of 3, 5 and 7
2. The sum of the digits can be divided by 3, 5 and 7 without remainder
3. The number can be divided by 3, 5 and 7 without remainder

I think 555555555555555555555555555555555555555555 is the smallest number that fulfils your homework's criteria, >>1-san.