This is one of the auto dialer numbers for United Healthcare insurance company, allegedly trying to reach one of their policyholders.  They have numerous numbers, so don't bother blocking the number, they'll just call you from a different number.  It was an exercise in frustration to find a number to call at United Healthcare to get my phone number removed from their database.  If they're blowing up your phone, call their Member Services number: 866-873-3903 to get your number blocked from their auto dialers.