21,804
21,804 is a composite number, even.
21,804 (twenty-one thousand eight hundred four) is an even 5-digit number. It is a composite number with 24 divisors, and factors as 2² × 3 × 23 × 79. Its proper divisors sum to 31,956, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x552C.
Interestingness
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 15
- Digit product
- 0
- Digital root
- 6
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 40,812
- Recamán's sequence
- a(40,231) = 21,804
- Square (n²)
- 475,414,416
- Cube (n³)
- 10,365,935,926,464
- Divisor count
- 24
- σ(n) — sum of divisors
- 53,760
- φ(n) — Euler's totient
- 6,864
- Sum of prime factors
- 109
Primality
Prime factorization: 2 2 × 3 × 23 × 79
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√21,804 = [147; (1, 1, 1, 22, 19, 1, 1, 1, 4, 3, 1, 4, 1, 10, 1, 72, 1, 10, 1, 4, 1, 3, 4, 1, …)]
Period length 32 — the block in parentheses repeats forever.
Representations
- In words
- twenty-one thousand eight hundred four
- Ordinal
- 21804th
- Binary
- 101010100101100
- Octal
- 52454
- Hexadecimal
- 0x552C
- Base64
- VSw=
- One's complement
- 43,731 (16-bit)
- Scientific notation
- 2.1804 × 10⁴
- As a duration
- 21,804 s = 6 hours, 3 minutes, 24 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵καωδʹ
- Mayan (base 20)
- 𝋢·𝋮·𝋪·𝋤
- Chinese
- 二萬一千八百零四
- Chinese (financial)
- 貳萬壹仟捌佰零肆
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,804 = 1
- e — Euler's number (e)
- Digit 21,804 = 6
- φ — Golden ratio (φ)
- Digit 21,804 = 2
- √2 — Pythagoras's (√2)
- Digit 21,804 = 6
- ln 2 — Natural log of 2
- Digit 21,804 = 8
- γ — Euler-Mascheroni (γ)
- Digit 21,804 = 1
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21804, here are decompositions:
- 5 + 21799 = 21804
- 17 + 21787 = 21804
- 31 + 21773 = 21804
- 37 + 21767 = 21804
- 47 + 21757 = 21804
- 53 + 21751 = 21804
- 67 + 21737 = 21804
- 103 + 21701 = 21804
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 94 AC (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.44.
- Address
- 0.0.85.44
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.85.44
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21804 first appears in π at position 184,126 of the decimal expansion (the 184,126ordinal-suffix:th digit after the integer 3).
Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.
Related reading
- Babylonian numerals — The base-60 cuneiform system that gave us 60 minutes, 60 seconds, and 360°.