What's listening on port 16385?

I'm running Ubuntu 16.04.5 LTS (GNU/Linux 4.17.8-x8664-linode110 x8664) on a Linode. Yesterday I applied some package updates ("apt-get upgrade") and noticed that something was now listening on port 16385. It wasn't before the package updates.

# netstat -an | grep 16385
tcp        0      0 0.0.0.0:16385           0.0.0.0:*               LISTEN

I rebooted, and something is still listening on this port.

I tried using "ss" to determine the owner process ID, but none was shown.

# ss -lptn 'sport = :16385'
State      Recv-Q Send-Q                                   Local Address:Port                                                  Peer Address:Port              
LISTEN     0      64  

I've tried a Google search, and can't find anything that uses 16385 as a well known port.

Any ideas on what's using this port or how to find that out?

Thanks!