About the Number 15 (fifteen)

This nBAB about the number 15 was created in order to complete nBABs for the numbers 10 through 19.

   MathBabbler Number Analyst (MBNA) output:
   =========================================
   15 is a natural, whole, integer
   15 is odd
   15 proper divisors are: 1,3,5,
   15 is deficient (sum of divisors is 9)
   15 is unhappy
   15 is not a Harshad number
   15 is not prime
   15 is undulating
   15 has the prime factors: 3*5
   15 is semiprime (biprime or 2-almost prime)
   15 in octal is 017
   15 in hexadecimal is 0xf
   15 in binary is 1111 (is evil)
   15 nearest square numbers: -6...1 (9...16 [4])
   sqrt(15) = 3.87298
   ln(15) = 2.70805
   log(15) = 1.17609
   15 reciprocal is .06666666666666666666666666666666
   15! is 1.30767e+12
   15 is 4.77465 Pi years
   15 is 0 score and 15 years
   15 written as a Roman numeral is XV

MathBabbler posted this nBAB for the number 15 immediately after posting a nBAB for the number 17 and 17 in octal (base-8) equals 15.

Note to MathBabbler: 15 is a Ruth-Aaron pair when repeated prime factors are counted. {Wikipedia.org::Ruth-Aaron Pair}

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 17 March 2009