Solr cloud production set up

[Rajdeep Sahoo]

Hi all,
 We are using solr cloud 7.7.1
In a live production environment how many solr cloud server do we need,
 Currently ,we are using master slave set up with 16 slave server with solr
4.6.
In solr cloud do we need to scale it up or 16 server will suffice the
purpose.