### About the Number 19,991 (nineteen thousand nine hundred ninety-one)

MathBabbler's rental car odometer hit 19,991 miles while driving on I-55 near Pontiac, Illinois. [7/4/2016]

```MathBabbler Number Analyst (MBNA) output:
=========================================
19991 is natural, counting, whole, integer
19991 is odd (not even)
19991 proper divisors are: 1,
19991 has 1 proper divisors
19991 is deficient (sum of divisors is 1; ratio: 5.00225e-05)
19991 is unhappy
19991 is a Squarefree Number
19991 is prime (not composite)
...Sexy prime with 19997
...Sexy Quadruple prime with 19979, 19985, 19997
...Sophie Germain prime with 39983
...Twin prime with 19993
...Truman Gerald (p+30) prime with 20021
...Truman Gerald (p-30) prime with 19961
...OEIS:002145 (4n+3; n=4997)
...reversible prime prime with 19991
...Right-truncatable prime
...Eisenstein (3n-1; n=6664)
...Strong prime
...prime triplet {19991, 19993, 19997}
19991 is palindromic
19991 is Arithmetic (A003601)
19991 in octal is 047027
19991 in binary is 100111000010111 (is evil)
19991 nearest square numbers: -110...173 (19881...20164 [142])
sqrt(19991) = 141.39
ln(19991) = 9.90304
log(19991) = 4.30083
19991 reciprocal is .00005002251012955830123555600020
19991 is an apocalyptic power (2^19991 contains 666)
19991! is inf
19991 is 6363.33 Pi years
19991 is 999 score and 11 years
19991 is 9996^2 - 9995^2 and 9996 + 9995 = 19991
19991 is a multiple of 1 & it contains a 1 (A011531)
```

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 06 July 2016