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21,864

21,864 is a composite number, even.

This number doesn't have a permanent NumberWiki page yet — what you see below is computed live. Pages get added to the permanent index when they're notable (years, primes, curated, etc.).
Abundant Number Arithmetic Number Gapful Number Odious Number Pernicious Number Recamán's Sequence Self Number Semiperfect Number

Properties

Parity
Even
Digit count
5
Digit sum
21
Digit product
384
Digital root
3
Palindrome
No
Bit width
15 bits
Reversed
46,812
Recamán's sequence
a(168,035) = 21,864
Square (n²)
478,034,496
Cube (n³)
10,451,746,220,544
Divisor count
16
σ(n) — sum of divisors
54,720
φ(n) — Euler's totient
7,280
Sum of prime factors
920

Primality

Prime factorization: 2 3 × 3 × 911

Nearest primes: 21,863 (−1) · 21,871 (+7)

Divisors & multiples

All divisors (16)
1 · 2 · 3 · 4 · 6 · 8 · 12 · 24 · 911 · 1822 · 2733 · 3644 · 5466 · 7288 · 10932 (half) · 21864
Aliquot sum (sum of proper divisors): 32,856
Factor pairs (a × b = 21,864)
1 × 21864
2 × 10932
3 × 7288
4 × 5466
6 × 3644
8 × 2733
12 × 1822
24 × 911
First multiples
21,864 · 43,728 (double) · 65,592 · 87,456 · 109,320 · 131,184 · 153,048 · 174,912 · 196,776 · 218,640

Sums & aliquot sequence

As consecutive integers: 7,287 + 7,288 + 7,289 1,359 + 1,360 + … + 1,374 432 + 433 + … + 479
Aliquot sequence: 21,864 32,856 51,564 68,780 84,100 104,907 58,417 1 0 — terminates at zero

Representations

In words
twenty-one thousand eight hundred sixty-four
Ordinal
21864th
Binary
101010101101000
Octal
52550
Hexadecimal
0x5568
Base64
VWg=
One's complement
43,671 (16-bit)
In other bases
ternary (3) 1002222210
quaternary (4) 11111220
quinary (5) 1144424
senary (6) 245120
septenary (7) 120513
nonary (9) 32883
undecimal (11) 15477
duodecimal (12) 107a0
tridecimal (13) 9c4b
tetradecimal (14) 7d7a
pentadecimal (15) 6729

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺
Greek (Milesian)
͵καωξδʹ
Mayan (base 20)
𝋢·𝋮·𝋭·𝋤
Chinese
二萬一千八百六十四
Chinese (financial)
貳萬壹仟捌佰陸拾肆
In other modern scripts
Eastern Arabic ٢١٨٦٤ Devanagari २१८६४ Bengali ২১৮৬৪ Tamil ௨௧௮௬௪ Thai ๒๑๘๖๔ Tibetan ༢༡༨༦༤ Khmer ២១៨៦៤ Lao ໒໑໘໖໔ Burmese ၂၁၈၆၄

Digit at this position in famous constants

π — Pi (π)
Digit 21,864 = 0
e — Euler's number (e)
Digit 21,864 = 9
φ — Golden ratio (φ)
Digit 21,864 = 3
√2 — Pythagoras's (√2)
Digit 21,864 = 4
ln 2 — Natural log of 2
Digit 21,864 = 0
γ — Euler-Mascheroni (γ)
Digit 21,864 = 5

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21864, here are decompositions:

  • 5 + 21859 = 21864
  • 13 + 21851 = 21864
  • 23 + 21841 = 21864
  • 43 + 21821 = 21864
  • 47 + 21817 = 21864
  • 61 + 21803 = 21864
  • 97 + 21767 = 21864
  • 107 + 21757 = 21864

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5568
U+5568
Other letter (Lo)

UTF-8 encoding: E5 95 A8 (3 bytes).

Hex color
#005568
RGB(0, 85, 104)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.85.104.

Address
0.0.85.104
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.85.104

Unspecified address (0.0.0.0/8) — "this network" placeholder.

Position in π

The digit sequence 21864 first appears in π at position 148,377 of the decimal expansion (the 148,377ordinal-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.