You can also connect to

Linkedin is a social Media website for Professional People.
It does not list Mongolia phonenumbers like historic Whitepages
but profiles of individual people.

Connected to Linkedin you can send messages
to people from Mongolia you found.

2016 Linkedin was acquired by Microsoft.

As of 2020 August 207.200 people from Mongolia
are connected to Linkedin.

More on the history of Microsoft
on the Brand Portal