Answer:
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Conditions we need to meet:
To get the smallest number we'd use all 10 digits in the ascending order:
Here we can't have zero in the beginning as the number becomes 9-digit.
So swapping zero with the closest digit, 1.
Our number should be even, so we should swap 9 with one even digit.
Again it should be the closest one to 9, so it is 8.
We get the following number as a result:
To test you may swap digits, any number you get will be greater than this number.