19 was a number.
The First Rani's time brain thought that 87K to the power of 19E correlated with 52 to the power of 6.4 equals 29V. The Seventh Doctor corrected it to 39. (TV: Time and the Rani [+]Pip & Jane Baker, Doctor Who season 24 (BBC1, 1987).)
Rose Tyler was nineteen years old when she met and began travelling with the Ninth Doctor. (TV: Rose [+]Russell T Davies, Doctor Who series 1 (BBC One, 2005)., Dalek [+]Robert Shearman, adapted from Jubilee (Robert Shearman), Doctor Who series 1 (BBC One, 2005)., PROSE: Rose Tyler [+]BBC webteam, U.N.I.T. (BBC, 2005)., The Doctor Was Involved in the Dummy Massacre [+]BBC webteam, Who is Doctor Who? (BBC, 2005).) However, other accounts indicated she was around seventeen. (TV: Father's Day [+]Paul Cornell, Doctor Who series 1 (BBC One, 2005)., Rise of the Cybermen [+]Tom MacRae, adapted from Spare Parts (Marc Platt), Doctor Who series 2 (BBC One, 2006)., PROSE: Meet Rose [+]Russell T Davies, Doctor Who Annual 2006 (Panini UK, 2005).)
Chronon, (WC: 14682 UNIT Field Log [+]UNIT Field Log (2020)., 14683 UNIT Field Log [+]UNIT Field Log (2020)., 14684 UNIT Field Log [+]UNIT Field Log (2020).) or cronon (WC: 14681 UNIT Field Log [+]UNIT Field Log (YouTube, 2020).) and artron energy readings during the recording of UNIT field logs included 17%, (WC: 14682 UNIT Field Log [+]UNIT Field Log (2020).) 18%, 19%, (WC: 14681 UNIT Field Log [+]UNIT Field Log (YouTube, 2020)., 14682 UNIT Field Log [+]UNIT Field Log (2020).) 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, (WC: 14682 UNIT Field Log [+]UNIT Field Log (2020).) 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, (WC: 14682 UNIT Field Log [+]UNIT Field Log (2020)., 14684 UNIT Field Log [+]UNIT Field Log (2020).) 90%, (WC: 14682 UNIT Field Log [+]UNIT Field Log (2020)., 14683 UNIT Field Log [+]UNIT Field Log (2020).) 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 100%, 101%, 102%, 103%, 104%, 105%, 106%, and, in the case of Chronon energy, 107%. (WC: 14683 UNIT Field Log [+]UNIT Field Log (2020).)