I enjoyed this post by Jason Quey which echoes many of my own feelings. Clients are often asking us for tips to create the optimal Passle post - how long? how short? what title? and so forth.
The answer of course is that it's going to be different depending on your followers. To take two of our clients, what works for the FinTech Collective (short summaries of breaking news), isn't the same as what is going to work for elXtr (considered yet snappy investigations). Read both and you'll see considerable differences in tone, style, length - which is at it should be!
What we can do is tell you what has worked across the network in general, which I did here.
You can use this as a starting point, if helpful, but the great thing about creating content easily is that you can get better at creating content that works for your audience. Get started, that's the hardest thing, and look back later to see which of your posts worked best.
Chances are, the number of words had nothing to do with the success of your best performing posts. What made them successful were that they were useful, entertaining, or just the right thing at the right time for your audience.
That's less satisfying than aiming for 222 words with each post, I know, but it's more honest.