Simplify

$\sqrt{27}=3\sqrt{3}$

$\sqrt{12}=2\sqrt{3}$

$\sqrt{147}=7\sqrt{3}$

$\sqrt{27}\cdot\sqrt{12}\cdot\sqrt{147}=3\cdot2\cdot7\cdot\sqrt{3}^3$

$42\cdot3\cdot\sqrt{3}$

$126\sqrt{3}$