### 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 )
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) 