I think its more then 20
987,653
The greatest 4-digit number with no repeated digits is... 9876
94205 if digits are not to be repeated and 99999 if digits can be repeated
763920
987,654
98,764
987,653
There is only one number and that is 123456.
The greatest 4-digit number with no repeated digits is... 9876
2000
98,764
94205 if digits are not to be repeated and 99999 if digits can be repeated
763920
9876543.
987654
98,764
9876543