I keep getting "Your Apple ID Verification Code" alerts

I got a new phone number about two weeks ago. Yesterday afternoon I started getting a lot of text alerts (see image below), that state my Apple ID Verification Code is: ######.

These are coming from two sources - 504-72 and 819-61. Are those actual Apple texts/alerts?

As a note, I am not trying to log into anything. Some come rapid fire within a minute or two of each other. Some a few hours apart.

I called tech support this afternoon and they had me change my password so I created the most hideously long and obnoxious one I ever had. I also updated my iphone with the new password.

Five hours later I got four more alerts, all within 5 minutes of each other.

I can't reach tech support now because it is after hours. This is MADDENING and very concerning.

Any ideas on what could be causing this and how to stop it?