To optimize the efficiency of a silicon-based micro-catalyst, chemical engineers design the catalyst particles in the shape of a regular square-based pyramid. One such particle has a square base of side length 18 μm18\ \mu\text{m}18 μm and a vertical height of 12 μm12\ \mu\text{m}12 μm.
Determine the surface area to volume ratio of this micro-catalyst particle in its simplest integer form.