Who called from 4243123447

Got a call on my cell phone this morning.  I did not answer as I didn't recognize the number and I don't know anyone in California.  They did not leave a message, however another website says it is the old IRS scam.  The call also originated from a cell phone, like the IRS would use cell phones for business.

I have received several calls at home from this number with a message saying 'final notice the IRS will begin legal action unless you call....'