You can distribute singles that are long as long as the release is truly a single track.
However, if there are natural breaks and stops in the content you must separate the release into tracks and distribute it as an album. Digital stores prefer that content is formatted this way as it creates a better listening experience for their customers and your fans.
Note, if a track is 10 minutes or longer, iTunes automatically marks the track as "album only" and bumps the price up to $9.99.
We are able to change the price for you in iTunes (although we cannot control your song being marked as “album only” as that is iTunes store policy). Learn more .
We can also mark a single "album only" in Amazon Music, which would raise the price to that of an album. Contact us to do this .
As for pricing in the other stores, we have no control over that and it could get priced at around $0.99. You might consider limiting your release to iTunes and Amazon for this reason.