You can do the following:
>>> utctime.isoformat()
'1601-01-01T00:00:00.000050'
Now if you want to have exactly the same format as above:
iso = utctime.isoformat()
tokens = iso.strip().split("T")
last_visit_time = "Last visit time: %s %s" % (tokens[0], tokens[1].strip().split(".")[0])
Not that there seems to be a patch for strftime
to fix this behavior here (not tested)