07700 900461
From Tardis Wiki, the free Doctor Who reference
07700 900461 was a telephone number used by the Doctor, each time on two distinct handsets.
In the 21st century, the Sub-Wave Network contacted the Tenth Doctor on this number, reaching the phone Martha Jones had previously given to him. (TV: The Stolen Earth)
McGillop of UNIT recognised 0700 900461 as a number associated with the Doctor when the Eleventh Doctor called him, although this time the Doctor used the phone that was connected to the exterior of his TARDIS. (TV: The Day of the Doctor)
It was later changed to 95475949. (COMIC: The Swords of Kali)
