The smallest multiple of 9 with no odd digits is 0.*
The smallest non-zero multiple of 9 with no odd digits can be either 288 or -288.*
The smallest non-zero, positive multiple of 9 with no odd-digits is 288.
*[The mathematical definition of a multiple is the result of multiplying a number by an integer. This definition aside, often it is in reference to a non-zero, positive integer.]
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