Get Current Blog ID


I would like to call the currently viewed blogs id and assign it to a variable.. much like get_current_site->id but for the blogs id.

right now I have this,

$current_site = get_current_site();
echo 'You are viewing '.$current_site->site_name;
echo 'You are viewing id '.$current_site->id;

but that calls the sites id, not the blogs id. Any help here?