1 Kings 9:23

23 They were also the chief officials in charge of Solomon’s projects—550 officials supervising those who did the work.

Read 1 Kings 9:23 Using Other Translations

These were the chief of the officers that were over Solomon's work, five hundred and fifty, which bare rule over the people that wrought in the work.
These were the chief officers who were over Solomon's work: who had charge of the people who carried on the work.
Solomon appointed 550 of them to supervise the people working on his various projects.