There are 320 such numbers.
279,999,720
There are none.
The sum of the digits is 6.
There are only five distinct odd digits.
952 of them.
405
10*9*8=720
There are 120 of them.
The sum of all the digits of all the positive integers that are less than 100 is 4,950.
279,999,720
9*9*8*7 = 4536
50%
Three of them.
They are 13.
There are 21.
52
There are none.