How can I see which wifi channel, frequency is used by my android 4.4.2 device?
This answer might be helpful for you. However, there are multiple apps could do that. Search wifi on google play. For example, the one I use at work and home is Wifi Analyzer. which graphically shows the channel & frequency for all wifi networks around plus the one you're connected to. I used this app on Samsung galaxy S2. I would post couple of screenshots taken by me but I can't post more than 2 links (new user).
In regards to what Wi-Fi channel your device is on you'll need to view the settings of the network that you're connected to.
This all depends on whether you have access to the network settings and what type of router it is. This will help you understand it more: http://www.pcadvisor.co.uk/how-to/network-wifi/3325316/how-change-wi-fi-channel/