Lol.
That's like my phone number but it's connected to my WhatsApp account which means I can chat with anyone in the world so long as they are on WhatsApp and I have their number or they have mine.
WhatsApp is a social media mainly for chatting with friends and it's quite popular,owned by Mark Zuckeberg who happens to be the owner of Facebook too.
It's quite easy to download and install the app from GooglePlayStore,so long as you have a phone that can download and install apps from it.
Just search for WhatsApp on it,download the app and create your account in it.
Takes less than 10 minutes to get it all setup.
While I know we could always keep talking directly using these replies, it just feels odd to me.
But nevermind, if you prefer these,sure.