### About the Number 85 (eighty-five)

Bettie Page died at the age of 85 on 11 December 2008. MathBabbler's mother is named Betty (actually Elizabeth, but MathBabbler has only known her as Betty).

```   MathBabbler Number Analyst (MBNA) output:
=========================================
85 is a natural, whole, integer
85 is odd
85 proper divisors are: 1,5,17,
85 is deficient (sum of divisors is 23)
85 is unhappy
85 is not a Harshad number
85 is not prime
85 is undulating
85 has the prime factors: 5*17
85 in octal is 0125
85 in hexadecimal is 0x55
85 in binary is 1010101 (is evil)
85 nearest square numbers: -4...15 (81...100 )
sqrt(85) = 9.21954
ln(85) = 4.44265
log(85) = 1.92942
85 reciprocal is .01176470588235294117647058823529
85! is 2.8171e+128
85 is 27.0563 Pi years
85 is 4 score and 5 years
```

`85` written as a Roman numeral is `LXXXV`.

`85` is a semi-prime (i.e. it has only two prime factors).

`85` is a 7th centered square number.

```   C(n) = n^2 + (n - 1)^2
C(7) = 7^2 + (7 - 1)^2 = 7^2 + 6^2 = 49 + 36 = 85
```

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 12 December 2008 (nBAB# 87) 