what are iss-realsec ,nrpe ,cbt services and are they good?
Note: Partial answer to address "what are these services".



About ISS-Realsec


PORT     STATE    SERVICE     VERSION
2998/tcp filtered iss-realsec



According to this manual on Nmap:

iss-realsec 2998/tcp    0.000351    # ISS RealSecure IDS Remote Console Admin port


On querying Google for ISS RealSecure IDS Remote Console Admin port, though obvious, various sources points that the port is used by ISS's Realsecure software, a Network based Intrusion Detection System (NIDS).  Info from few sources is mentioned below.


European Union Agency for Network and Information Security mentions it as:


  ISS RealSecure is a commercial firewall/IDS package, designed to provide security protection for large, complex networks. Sensors can take input from hosts or networks and report anonmalies back to a central management station.
  
  Source: http://www.iss.net/
  Platform:
  
  
  Windows
  Unix
  

Network Security Resource and SANS also has the similar info here and here, respectively.


Note that ISS stands for Internet Security Systems which is now, IBM Internet Security Systems.

About NRPE


 PORT     STATE    SERVICE     VERSION
 5666/tcp filtered nrpe



According to this manual on Nmap:


nrpe  5666/tcp    0.006614    # Nagios NRPE



Querying Google for Nagios NRPE gives result, more or less similar, and is mentioned below.


Nagios on its exchange website states that:


  NRPE [addon] allows you to remotely execute Nagios plugins on other Linux/Unix machines. This allows you to monitor remote machine metrics (disk usage, CPU load, etc.). NRPE can also communicate with some of the Windows agent addons, so you can execute scripts and check metrics on remote Windows machines as well.


(See similar info on Wikipedia.) 
What is Nagios? What does it do?


  Nagios is a powerful monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes.
  
  By using Nagios, you can:
  
  
  Plan for infrastructure upgrades before outdated systems cause failures
  Respond to issues at the first sign of a problem
  Automatically fix problems when they are detected
  Coordinate technical team responses
  Ensure your organization's SLAs are being met
  Ensure IT infrastructure outages have a minimal effect on your organization's bottom line
  Monitor your entire infrastructure and business processes
  



About CBT


 7777/tcp filtered cbt



The aforementioned guide for Nmap doesn't have any information to lead. 


Querying Google for such results this page et al. which states:


 Service                                                                    [Default TCP]     Notes
 Oracle HTTP Server non-SSL or Oracle9iAS Web Cache HTTP Listen non-SSL     7777              This port is IANA-registered for "cbt" by cs.ucl.ac.uk



(IANA here doesn't have useful info other than the name of the Assignee. )
Wikipedia has the following info :


 Port     TCP     UDP     Description                                             Status
 7777     TCP             iChat server file transfer proxy                        Unofficial
 7777     TCP             Oracle Cluster File System 2                            Unofficial
 7777     TCP             Windows backdoor program tini.exe default               Unofficial
 7777     TCP             Just Cause 2: Multiplayer Mod Server                    Unofficial
 7777     TCP             Xivio default Chat Server                               Unofficial
 7777     TCP             Terraria default server                                 Unofficial
 7777             UDP     San Andreas Multiplayer (SA-MP) default port server     Unofficial



(There can be a malware running on this port as noted here. Also, Oracle has a link here using Netcat (nc) to connect to a machine using 7777 port.)


About Airdroid


PORT     STATE    SERVICE     VERSION
8888/tcp open     http        AirDroid httpd 2.0



Based on the info in the question and my own experience, Airdroid uses this port to host a server on your phone so that a user can access it through a browser.

What is Airdroid?


  AirDroid is a free and fast Android device manager app that allows you to access Android phone/tablet from computer remotely and securely. Manage SMS, files, photos and videos, WhatsApp, Line, WeChat and more on computer.


(Click here to see Airdroid's usage guide which uses port 8888.)



Other than port 8888, I can't comment possibly why your android device has these open ports which reflects services that are not known for Android at least, which makes this answer not very useful to resolve the question but enough to lead you further :-)