An estimated 25.6 million viewers watched Vecepia “Vee” Towery, 36, an office manager from Portland, Ore., pick up $1 million by beating Neleh Dennis, 21, a psychology student from Layton, Utah, Sunday night at the conclusion of CBS’s “Survivor: Marquesas,” according to preliminary ratings figures reported by the Associated Press. Though the numbers were impressive and made CBS the ratings champ of that very competitive Sunday, they nonetheless made this “Survivor 4” wrap-up the least-watched finale of the reality series. The first “Survivor” finale, in August 2000, captured nearly twice as many viewers. And January’s finale of “Survivor: Africa” nabbed 27 million viewers. As for the competition, NBC battled “Survivor” with a reunion special for the ’80s favorite “The Cosby Show”; Fox aired the series finale (after nine years) of “The X-Files”; and ABC dished up a two-hour, season-ending episode of “The Practice.” Their numbers: NBC proved strong, with 18.3 million viewers for “Cosby,” while “The Practice” grabbed 13.2 million viewers, about 400,000 more than it attracted for a typical episode this season. “The X-Files” conclusion drew 13 million — its largest audience since last season’s finale. The truth will remain out there in syndication.