Rang twice and it hung up as I was about to answer.

Immediately got a voice mail from a different number - taking about "ringless voicemail". Jerk telemarketers.

Rang twice and hung up. Sure it's spammer

Rings twice then hangs up.
A minute or two later a call from 714-868-0162 shows up with a spam voicemail without the phone ever ringing.

I believe these two numbers are connected.
Spam!!

Yes, the 2 numbers starting with 646 and 714 are related to one another.  Only the 646 number showed up on my cell phone list of incoming calls, but the 714 number was the one that left a message about some gwak ring thing