$\large {\left(\sqrt[4]{x}\right)}^{4x^4} = {\left(x^4\right)}^{4\sqrt[4]{x}}$

Find the real value of $x$ that satisfies the equation above.

If the answer is of the form $a × \sqrt[15]{b},$ then submit the value of $a + b.$

**Note:** Here, $x \neq 0,1$.