The 3rd Friday the 13th for 2015 was on day number

317of the year.MathBabbler Number Analyst (MBNA) output: ========================================= 317 is a natural, whole, integer 317 is odd 317 proper divisors are: 1, 317 has 1 proper divisors 317 is deficient (sum of divisors is 1; ratio: 0.00315457) 317 is unhappy 317 is a Squarefree Number 317 is prime (not composite) ...Cousin prime with 313 ...Sexy prime with 311 ...Truman Gerald prime with 347 ...Pythagorean ...Left-truncatable ...Right-truncatable ...Eisenstein ...prime triplet {311, 313, 317} 317 is Arithmetic (A003601) 317 in octal is 0475 317 in hexadecimal is 0x13d 317 in binary is 100111101 (is evil) 317 nearest square numbers: -28...7 (289...324 [18]) sqrt(317) = 17.8045 ln(317) = 5.7589 log(317) = 2.50106 317 reciprocal is .00315457413249211356466876971608 317! is 6.51882e+656 317 is 100.904 Pi years 317 is 15 score and 17 years 317 written as a Roman numeral is CCCXVII 317 is 159^2 - 158^2 and 159 + 158 = 317 317 is a multiple of 1 & it contains a 1 (A011531)

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

**Created:** 13 November 2015

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