Ask HN: Securing My Phone Number

Phone numbers are becoming ubiquitous two factor authentication channels (or one factor, because some services allow a reset via SMS) for critical services like email addresses, domain names, and financial accounts.

Are there any best practices to secure my phone number against malevolent actors who want to hijack it or intercept its incoming SMS/calls/voicemails? Are there any carriers that are better or worse than average at preventing these attacks?

I live in the US but feel free to share about other international carriers as well.