lots of open ports, but not sure what they are being used for

I ran a port scanner to see which ports were open to the public and found a lot of ports which I'm not familiar with. Is there a way to figure out which ports I can safely close to the public?

80/tcp   open   http

110/tcp  open   pop3

143/tcp  open   imap

443/tcp  open   https

465/tcp  open   smtps

587/tcp  open   submission

993/tcp  open   imaps

995/tcp  open   pop3s

2030/tcp open   device2

2031/tcp open   mobrien-chat

2082/tcp open   infowave

2083/tcp open   radsec

2086/tcp open   gnunet

2087/tcp open   eli

2095/tcp open   nbx-ser

2096/tcp open   nbx-dir

5050/tcp closed mmcc

7777/tcp open   cbt

all except 5050 and 7777 are cwp standard ports so you need to check only that two.

All well-known ports »
https://de.wikipedia.org/wiki/Liste_der_standardisierten_Ports

Pleas google first before making a forum request.
Thank you!