“The son of Uzzi was Izrahiah. The sons of Izrahiah were Michael, Obadiah, Joel, and Isshiah. All five of them were chief men. Along with them, by their generations, according to their ancestral houses, were units of the fighting force, thirty-six thousand, for they had many wives and sons. Their kinsmen belonging to all the families of Issachar were in all eighty-seven thousand mighty warriors, enrolled by genealogy.”
Uzzi had 1 son, Izrahiah, whose name only appears here. Izrahiah had 4 sons so that he and his 4 sons were the 5 chiefs of 36,000 fighting men. There are 11 people named (1) Michael, including an archangel. There were 12 different people with the name of (2) Obadiah. There were 14 people with the name of (3) Joel, with the most famous being the minor prophet whose book is Joel. Finally, there were 4 different people with the name of (4) Isshiah. When you count all the men of Issachar you had 87,000 mighty warriors, presumably at the time of David.