Imagine two spherical cells, one of which is 5000 times larger in volume than the other. The smaller is a prokaryote, and the larger cell is a eukaryote with 20% of its volume confined in a spherical nucleus. If the diameter of the prokaryotic cell is 0.7 micrometers, what is the diameter of the nucleus in the eukaryotic cell in micrometers? Write down your answer as a number only.