...could not find a reference to this number either here or on 'whocallsme" ...
...found this:
http://findwhocallsyou.com inserted the number
(5) responses so far
number five: home security (best likelihood)
notes:
caller on cellphone not house phone
called twice-I answered but no one on other end (robocall to test number only?)
called back-automatic disconnect
added to block list on cellphone
hope information is useful