About the Number 90 (ninety)

MathBabbler decided to create a nBAB for the number 90 because this is the 90th nBAB.

   MathBabbler Number Analyst (MBNA) output:
   =========================================
   90 is a natural, whole, integer
   90 is even
   90 proper divisors are: 1,2,3,5,6,9,10,15,18,30,45,
   90 is abundant (sum of divisors is 144)
   90 is unhappy
   90 is a Harshad number
   90 is not prime
   90 is undulating
   90 has the prime factors: 2*3*3*5
   90 in octal is 0132
   90 in hexadecimal is 0x5a
   90 in binary is 1011010 (is evil)
   90 nearest square numbers: -9...10 (81...100 [10])
   sqrt(90) = 9.48683
   ln(90) = 4.49981
   log(90) = 1.95424
   90 reciprocal is .01111111111111111111111111111111
   90! is 1.48572e+138
   90 is 28.6479 Pi years
   90 is 4 score and 10 years

90 written as a Roman numeral is XC.

90 equals the sum of the squares of the numbers two through six.

   2^2 + 3^2 + 4^2 + 5^2 + 6^2 = 4 + 9 + 16 + 25 + 36 = 90

An angle measuring 90 degrees minus Pi divided-by two radians is zero.

Update::2009.01.02

Claiborne Pell died at the age of 90 on 1 January 2009. In 1972, Pell sponsored program (Pell grants) that has "helped 54 million low- and moderate-income students attend college."

Update::2009.03.01

Paul Harvey, a resident of Phoenix, Arizona, died at the age of 90 on 28 February 2009. MathBabbler says "Page 2" from time-to-time during class.

Update::2013.12.14

Pi Day 2014 was 90 days away on 14 December 2013.

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 17 December 2008 (nBAB #90)