alt Hacker NewsThe ads/analytics providers very well might. They gather data and cross-reference from tons of different sources.
And I don't know about you, but I've put my phone number into a lot of apps and sites. Sometimes it's required, sometimes it's for 2FA, etc.
I use a virtual number for almost all such signups (only doctors or other safety-related providers), so I'm not sure that would be a possible avenue for these calls, which come to my direct cell phone number. It is not quite a secret, but it is not something I give out to many companies.