I learned about Dunbar’s number
(~150) is the size of a community in which everyone knows each other’s identities and roles.
In anthropology class. You can ask someone to write down the name of everyone they can think of, real or fictional, live or dead and most people will not make it to 250.
Some individuals like professional gossip columnists or some politicians can remember as many as 1,000 people.
Dunbar's number is largely psuedoscience. Dunbar just took the group size of gorillas, scaled up to humans based on brain size, and then published, without bothering with silly little details like actually testing human group sizes.