The number of those chosen to be gatekeepers at the thresholds was 212. They were registered by genealogy in their villages. David and Samuel the seer had appointed them to their positions of trust.
KJV
All these [which were] chosen to be porters in the gates [were] two hundred and twelve. These were reckoned by their genealogy in their villages, whom David and Samuel the seer did ordain in their set office.
ASV
All these that were chosen to be porters in the thresholds were two hundred and twelve. These were reckoned by genealogy in their villages, whom David and Samuel the seer did ordain in their office of trust.