# Special Numbers

Logic Level 3

Suppose $$M$$ is a four-digit positive integer such that $$4M$$ is also a four-digit number and $$4M$$ has the same digits as $$M$$, but in the reverse order. Find the sum of all possible $$M$$.

As an illustration, if $$M$$ is of the form $$\overline{abcd}$$, then $$4M$$ is of the form $$\overline{dcba}$$, where $$a$$, $$b$$, $$c$$ and $$d$$ are digits.

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