### About the Number 421 (four hundred twenty-one)

nBABs (number Basic Arithmetic Bits) turned six years of age on 22 April 2011 and whe nBAB count was `421` on that date.

```   MathBabbler Number Analyst (MBNA) output:
=========================================
421 is a natural, whole, integer
421 is odd
421 proper divisors are: 1,
421 is deficient (sum of divisors is 1)
421 is unhappy
421 is not a Harshad number
421 is prime
...Twin prime with 419
...Pythagorean
421 is a lucky number
421 is the sum of 5 consecutive primes
421 = 73 + 79 + 83 + 89 + 97
421 in octal is 0645
421 in hexadecimal is 0x1a5
421 in binary is 110100101 (is odious)
421 nearest square numbers: -21...20 (400...441 )
sqrt(421) = 20.5183
ln(421) = 6.04263
log(421) = 2.62428
421 reciprocal is .00237529691211401425178147268408
421! is 4.96709e+923
421 is 134.008 Pi years
421 is 21 score and 1 year
421 written as a Roman numeral is CDXXI
421 = 211^2 - 210^2 and 211 + 210 = 421
```

`4215` equals repdigit number 111.

`4219` equals palindromic number 343.

Creator: Gerald Thurman [gthurman@gmail.com]
Created: 24 April 2011 