It is .56789
There are twelve possible solutions using the rule you stated... 13,14,17,31,34,37,41,43,47,71,73 & 74
Possible solutions - using your rules are:- 11,13,17,31,33,37,71,73 &77
1111, unless you allow negative number. In that case, the answer is -9999.
the largest five digit number that can be formed using the digits 7 and 9 is 97,000
ten factorial = 10! = 3,628,800
Assuming that the first digit of the 4 digit number cannot be 0, then there are 9 possible digits for the first of the four. Also assuming that each digit does not need to be unique, then the next three digits of the four can have 10 possible for each. That results in 9x10x10x10 = 9000 possible 4 digit numbers. If, however, you can not use the same number twice in completing the 4 digit number, and the first digit cannot be 0, then the result is 9x9x8x7 = 4536 possible 4 digit numbers. If the 4 digit number can start with 0, then there are 10,000 possible 4 digit numbers. If the 4 digit number can start with 0, and you cannot use any number twice, then the result is 10x9x8x7 = 5040 possilbe 4 digit numbers.
The key is to advance from left to right, and use the smallest possible digit in each case. Thus, the first digit must be at least 5 (for the number to be "greater than 500,000"), so you take 5 as the first digit. The smallest option for the second digit is 0, the smallest remaining digit for the third position is 1, etc.
I would not like a list all possible 4 digit combination using 0-9.
There are eighteen of them.
There are 60480 numbers.
Total possible 4-digit numbers= 1000, 1001,...,9999 = 9000 Total with same digit numbers = 1111,2222,...,9999 = 9 9000 - 9 = 8991
There are 210 4 digit combinations and 5040 different 4 digit codes.
There are twelve possible solutions using the rule you stated.
Proceed from left to right, using the largest possible digit in each position.
Assuming leading zeros are not permitted, then: If repeats are not allowed there are 30 possible numbers. If repeats are allowed there are 60 possible numbers.