Paul Harvey died at the age of 90. MathBabbler already had a nBAB for the number 90, but he didn't have a nBab for the numbers 89 and

`. This nBAB is for the number`

91`.`

91MathBabbler Number Analyst (MBNA) output: ========================================= 91 is a natural, whole, integer 91 is odd 91 proper divisors are: 1,7,13, 91 is deficient (sum of divisors is 21) 91 is happy 91 is not a Harshad number 91 is not prime 91 is undulating 91 has the prime factors: 7*13 91 is semiprime (biprime or 2-almost prime) 91 in octal is 0133 91 in hexadecimal is 0x5b 91 in binary is 1011011 (is odious) 91 nearest square numbers: -10...9 (81...100 [10]) sqrt(91) = 9.53939 ln(91) = 4.51086 log(91) = 1.95904 91 reciprocal is .01098901098901098901098901098901 91! is 1.352e+140 91 is 28.9662 Pi years 91 is 4 score and 11 years 91 written as a Roman numeral is XCIThis was the

`st BAB posted during the Spring 2009 BABbling session.`

91

`[Wikipedia]`

`is the "smallest positive integer expressible as a sum of two cubes in two different ways if negative roots are allowed:`

91`= 6^3+(-5)^3 = 4^3+3^3.`

91MathBabbler needs to look more closely at the McCarthy 91 function.

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

**Created:** 01 March 2009

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