The number of galaxies within a megaparsec (Mpc) of space can vary depending on the region and density of the universe. A megaparsec is a unit of length equal to one million parsecs, where a parsec is approximately 3.09 million light-years.
On average, the current estimates suggest that there are roughly 0.02 to 0.1 galaxies per cubic megaparsec, based on observations of large-scale structures in the universe. This means that within a single megaparsec, you can expect to find approximately 20,000 to 100,000 galaxies.
However, it's important to note that this estimation is subject to uncertainties and variations across different regions of the universe. The distribution of galaxies is not uniform, and there are regions with higher galaxy densities (clusters) and regions with lower densities (voids). These numbers represent an average value and can vary significantly in different cosmic environments.