Unable to retrieve youtube username

I do have channelId of a channel. But now I want to get the username of that channel (NOT TITLE). I have used following request and I got many details like likes, views, title, description but it is not providing with the username.https://www.googleapis.com/youtube/v3/channels?part=snippet,contentDetails,statistics&id=UCgT2O93IiQT3XdpQYI6KDYQ&maxResults=10&key=123456789P.S I've used my api_key properly.