21,824
21,824 is a composite number, even.
21,824 (twenty-one thousand eight hundred twenty-four) is an even 5-digit number. It is a composite number with 28 divisors, and factors as 2⁶ × 11 × 31. Its proper divisors sum to 26,944, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x5540.
Interestingness
Properties
- Parity
- Even
- Digit count
- 5
- Digit sum
- 17
- Digit product
- 128
- Digital root
- 8
- Palindrome
- No
- Bit width
- 15 bits
- Reversed
- 42,812
- Recamán's sequence
- a(168,115) = 21,824
- Square (n²)
- 476,286,976
- Cube (n³)
- 10,394,486,964,224
- Divisor count
- 28
- σ(n) — sum of divisors
- 48,768
- φ(n) — Euler's totient
- 9,600
- Sum of prime factors
- 54
Primality
Prime factorization: 2 6 × 11 × 31
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√21,824 = [147; (1, 2, 1, 2, 3, 2, 1, 1, 1, 11, 5, 3, 2, 73, 2, 3, 5, 11, 1, 1, 1, 2, 3, 2, …)]
Period length 28 — the block in parentheses repeats forever.
Representations
- In words
- twenty-one thousand eight hundred twenty-four
- Ordinal
- 21824th
- Binary
- 101010101000000
- Octal
- 52500
- Hexadecimal
- 0x5540
- Base64
- VUA=
- One's complement
- 43,711 (16-bit)
- Scientific notation
- 2.1824 × 10⁴
- As a duration
- 21,824 s = 6 hours, 3 minutes, 44 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵καωκδʹ
- Mayan (base 20)
- 𝋢·𝋮·𝋫·𝋤
- Chinese
- 二萬一千八百二十四
- Chinese (financial)
- 貳萬壹仟捌佰貳拾肆
Digit at this position in famous constants
- π — Pi (π)
- Digit 21,824 = 8
- e — Euler's number (e)
- Digit 21,824 = 7
- φ — Golden ratio (φ)
- Digit 21,824 = 1
- √2 — Pythagoras's (√2)
- Digit 21,824 = 0
- ln 2 — Natural log of 2
- Digit 21,824 = 5
- γ — Euler-Mascheroni (γ)
- Digit 21,824 = 1
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21824, here are decompositions:
- 3 + 21821 = 21824
- 7 + 21817 = 21824
- 37 + 21787 = 21824
- 67 + 21757 = 21824
- 73 + 21751 = 21824
- 97 + 21727 = 21824
- 151 + 21673 = 21824
- 163 + 21661 = 21824
Showing the first eight; more decompositions exist.
UTF-8 encoding: E5 95 80 (3 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.64.
- Address
- 0.0.85.64
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.85.64
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 21824 first appears in π at position 30,153 of the decimal expansion (the 30,153ordinal-suffix:rd 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
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.