9-digit Number Puzzle - Solution

What 9-digit number has the following features:

It has all 9 digits from 1 to 9

It is evenly divisible by 6 and 7

Each time it is rounded (starting with units, then tens, hundreds, etc) it rounds in an alternate pattern (up, down, up ...), until after rounding 8 times the final number is 500000000

After rounding four times the sum of the digits is 24