45 was a number.
Frobisher was 45 years old when he met the Sixth Doctor. (COMIC: The Shape Shifter)
Mrs Crisp aimed to make the IQ of everybody 45 but she was stopped by the Seventh Doctor, Ace and Hex. (AUDIO: Order of Simplicity)
There were 45 cousins in the House of Lungbarrow on Gallifrey, including the Doctor. (PROSE: Cat's Cradle: Time's Crucible, Lungbarrow)