Number
21,821
21,821 is a prime, odd.
Properties
- Parity
- Odd
- Digit count
- 5
- Digit sum
- 14
- Digital root
- 5
- Palindrome
- No
- Divisor count
- 2
- σ(n) — sum of divisors
- 21,822
Primality
21,821 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Aliquot sum (sum of proper divisors):
1
First multiples
Representations
- In words
- twenty-one thousand eight hundred twenty-one
- Ordinal
- 21821st
- Binary
- 101010100111101
- Octal
- 52475
- Hexadecimal
- 553D
Also seen as
Prime neighborhood
Unicode codepoint
唽
U+553D
Other letter (Lo)
UTF-8 encoding: E5 94 BD (3 bytes).
Hex color
#00553D
RGB(0, 85, 61)
IPv4 address
As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.61.