27 (number)

27 was a number.

At one point during their failure, a Kroton calculated they would have to reserve power for 27 further minutes before it exhausted. (TV: The Krotons)

Vega 3 was 27 light-years from Earth. (PROSE: K9 and the Beasts of Vega)

Through use of a magnetron, the New Dalek Empire transported 27 stolen planets from across time and space to the Medusa Cascade, where they collectively served as an engine for the Daleks' reality bomb. (TV: The Stolen Earth/Journey's End)

Behind the scenes
In NOTVALID: The Curse of Fatal Death, the Ninth Doctor calculates that he has saved every planet in the known universe a minimum number of 27 times.