### About the Number 87 (eighty-seven)

MathBabbler came across a BARS that was created for a road sign in which no math was found. One week earlier, a BARS was chosen for BOTW that had a sign for which no math was initially found. In both cases the number 87 was the source of the problem.

```   MathBabbler Number Analyst (MBNA) output:
=========================================
87 is a natural, whole, integer
87 is odd
87 proper divisors are: 1,3,29,
87 is deficient (sum of divisors is 33)
87 is unhappy
87 is not a Harshad number
87 is not prime
87 is undulating
87 has the prime factors: 3*29
87 in octal is 0127
87 in hexadecimal is 0x57
87 in binary is 1010111 (is odious)
87 nearest square numbers: -6...13 (81  ...100 )
sqrt(87) = 9.32738
ln(87) = 4.46591
log(87) = 1.93952
87 reciprocal is .01149425287356321839080459770114
87! is 2.10776e+132
87 is 27.693 Pi years
87 is 4 score and 7 years
```

`87` in Roman numeral is `LXXXVII`.

The Wikipedia said: `87` is the sum of the squares of the first four primes.

```   2^2 + 3^2 + 5^2 + 7^2 = 4 + 9 + 25 + 49 = 87
```

The Wikipedia also said: `87` is the sum of the sum of divisors of the first ten integers.

```    1:  1
2:  1 + 2 = 3
3:  1 + 3 = 4
4:  1 + 2 + 4 = 7
5:  1 + 5 = 6
6:  1 + 2 + 3 + 6 = 12
7:  1 + 7 = 8
8:  1 + 2 + 4 + 8 = 15
9:  1 + 3 + 9 = 13
10:  1 + 2 + 5 + 10 = 18

1 + 3 + 4 + 7 + 6 + 12 + 8 + 15 + 13 + 18 = 87
```

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 17 October 2008 