SEAMO 2019 — Paper C — Grade 5–6 Question 22

The three-digit number $\overline{abc}$ has distinct digits and satisfies $\overline{ab}+\overline{ba}+\overline{ac}+\overline{ca}+\overline{bc}+\overline{cb}=\overline{abc}$. The sum of its digits is a multiple of what number?