This is one of those IRS scam numbers.  They call you threatening you with arrest if you don't call back.  When you call back, they have your name, address and phone number, which are available to any telemarketer, so is not any indication that they are legitimate.  They then tell you that you owe some very specific amount (e.g., $6271.34) and that they are required to inform the police to issue and arrest warrant and come to your home immediately to arrest you the moment we end this call.  I didn't get to the part about how that would work (since that isn't how the IRS or arrest warrants work) before I told the person I knew this was a scam, and she immediately hung up on me.