Usually about 6 directs or so.

But you end up talking to all of them fairly often frankly cause any kind of drama / uncertainty gets delegated up pretty fast.

Poster didn't specify if it was direct reports or span of 20.

That said, if you are correct and it's direct reports - agree that's bad sign.

If it's indirect reports, that means there's an org tree 'beneath' you... How are you not already a manager in that case?

Right, that's what "span" means.

It would be a big step for a first management role, but not insane. The first time I did it got up to about that number in less than 3 months, so not day 1 but not far off it. This happened by having a regular sized (i.e half dozen) team first, and hiring another dozen person team soon after where it made sense to put them under my group.

The only reason we tried that is that a) things were going well and b) I had good mentorship in the role with the commitment of real help (i.e. time) from them if things started to get shaky.