Easy way to change phone number on Contact page

I want to be able to change my phone number on my website easily so that I can route incoming calls to me or another worker or answering service, etc. but I have a bunch of websites. So, I'm thinking of having my Contact Me page on all of my sites point to one certain page on one of my sites. So I have to only update one page to change my phone number. And I'd like to be able to easily change the phone number. I always have a smartphone in my pocket. So, what would be easiest?

I posted this request a couple of years ago (http://www.warriorforum.com/website-...via-email.html) and people said use Wordpress. But I want something simple. A text is probably simplest. An email would be simple. Using Wordpress, I don't know. And I would rather not have to manually type a new phone number. I'd rather it just be something like if I text "1" or "2" to a certain phone number, it would automatically populate my web page with the appropriate phone numbers which I have programmed into the script for "1" and "2." And the old (defunct) flexwindow.com service mentioned in the above old thread worked great... via email.

OTOH, if you think Wordpress would be simple, advise.

EDIT P.S. This needs to be something as easy as sending a text or an email. To have to login to a host is not ideal, but I'm open to considering it.