`January 2009 was Martin Luther King, Jr. Day.`

19MathBabbler Number Analyst (MBNA) output: ========================================= 19 is a natural, whole, integer 19 is odd 19 proper divisors are: 1, 19 is deficient (sum of divisors is 1) 19 is happy 19 is not a Harshad number 19 is prime ...Cousin prime with 23 ...Sexy prime with 13 ...Twin prime with 17 ...OEIS:002145 (4n+3; n=4) ...prime triplet {13, 17, 19} ...prime triplet {17, 19, 23} ...prime quadruplet {11, 13, 17, 19} 19 is undulating 19 in octal is 023 19 in hexadecimal is 0x13 19 in binary is 10011 (is odious) 19 nearest square numbers: -3...6 (16...25 [5]) sqrt(19) = 4.3589 ln(19) = 2.94444 log(19) = 1.27875 19 reciprocal is .05263157894736842105263157894736 19! is 1.21645e+17 19 is 6.04789 Pi years 19 is 0 score and 19 years 19 written as a Roman numeral is XIX

`is the last year a teenager is a teenager (at least numerically).`

19

`is 13 in base-16. [And 13 is the first year a teenager is a teenager.]`

19## Update::2014.06.04

**Creator:** Gerald Thurman
[gthurman@gmail.com]

**Created:** 18 January 2009

This work is licensed under a Creative Commons Attribution 3.0 United States License.