Vector Algebra: JEE Main 2021 Mathematics question

Let $\overrightarrow c$ be a vector perpendicular to the vectors, $\overrightarrow a$ = $\widehat i$ + $\widehat j$ $-$ $\widehat k$ and $\overrightarrow b$ = $\widehat i$ + 2$\widehat j$ + $\widehat k$. If $\overrightarrow c \,.\,\left( {\widehat i + \widehat j + 3\widehat k} \right)$ = 8 then the value of $\overrightarrow c$ . $\left( {\overrightarrow a \times \overrightarrow b } \right)$ is equal to __________.