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21,312

21,312 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 Happy Number Harshad / Niven Odious Number Palindrome Pernicious Number Practical Number Recamán's Sequence Semiperfect Number Zuckerman Number

Properties

Parity
Even
Digit count
5
Digit sum
9
Digit product
12
Digital root
9
Palindrome
Yes
Bit width
15 bits
Recamán's sequence
a(41,215) = 21,312
Square (n²)
454,201,344
Cube (n³)
9,679,939,043,328
Divisor count
42
σ(n) — sum of divisors
62,738
φ(n) — Euler's totient
6,912
Sum of prime factors
55

Primality

Prime factorization: 2 6 × 3 2 × 37

Nearest primes: 21,283 (−29) · 21,313 (+1)

Divisors & multiples

All divisors (42)
1 · 2 · 3 · 4 · 6 · 8 · 9 · 12 · 16 · 18 · 24 · 32 · 36 · 37 · 48 · 64 · 72 · 74 · 96 · 111 · 144 · 148 · 192 · 222 · 288 · 296 · 333 · 444 · 576 · 592 · 666 · 888 · 1184 · 1332 · 1776 · 2368 · 2664 · 3552 · 5328 · 7104 · 10656 (half) · 21312
Aliquot sum (sum of proper divisors): 41,426
Factor pairs (a × b = 21,312)
1 × 21312
2 × 10656
3 × 7104
4 × 5328
6 × 3552
8 × 2664
9 × 2368
12 × 1776
16 × 1332
18 × 1184
24 × 888
32 × 666
36 × 592
37 × 576
48 × 444
64 × 333
72 × 296
74 × 288
96 × 222
111 × 192
144 × 148
First multiples
21,312 · 42,624 (double) · 63,936 · 85,248 · 106,560 · 127,872 · 149,184 · 170,496 · 191,808 · 213,120

Sums & aliquot sequence

As a sum of two squares: 24² + 144²
As consecutive integers: 7,103 + 7,104 + 7,105 2,364 + 2,365 + … + 2,372 558 + 559 + … + 594 137 + 138 + … + 247
Aliquot sequence: 21,312 41,426 36,334 19,754 16,534 11,834 6,394 3,686 2,194 1,100 1,504 1,520 2,200 3,380 4,306 2,156 2,632 — unresolved within range

Representations

In words
twenty-one thousand three hundred twelve
Ordinal
21312th
Binary
101001101000000
Octal
51500
Hexadecimal
0x5340
Base64
U0A=
One's complement
44,223 (16-bit)
In other bases
ternary (3) 1002020100
quaternary (4) 11031000
quinary (5) 1140222
senary (6) 242400
septenary (7) 116064
nonary (9) 32210
undecimal (11) 15015
duodecimal (12) 10400
tridecimal (13) 9915
tetradecimal (14) 7aa4
pentadecimal (15) 64ac

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹 𒌋𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓎆𓏺𓏺
Greek (Milesian)
͵κατιβʹ
Mayan (base 20)
𝋢·𝋭·𝋥·𝋬
Chinese
二萬一千三百一十二
Chinese (financial)
貳萬壹仟參佰壹拾貳
In other modern scripts
Eastern Arabic ٢١٣١٢ Devanagari २१३१२ Bengali ২১৩১২ Tamil ௨௧௩௧௨ Thai ๒๑๓๑๒ Tibetan ༢༡༣༡༢ Khmer ២១៣១២ Lao ໒໑໓໑໒ Burmese ၂၁၃၁၂

Digit at this position in famous constants

π — Pi (π)
Digit 21,312 = 6
e — Euler's number (e)
Digit 21,312 = 3
φ — Golden ratio (φ)
Digit 21,312 = 5
√2 — Pythagoras's (√2)
Digit 21,312 = 0
ln 2 — Natural log of 2
Digit 21,312 = 6
γ — Euler-Mascheroni (γ)
Digit 21,312 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21312, here are decompositions:

  • 29 + 21283 = 21312
  • 43 + 21269 = 21312
  • 101 + 21211 = 21312
  • 149 + 21163 = 21312
  • 163 + 21149 = 21312
  • 173 + 21139 = 21312
  • 191 + 21121 = 21312
  • 211 + 21101 = 21312

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5340
U+5340
Other letter (Lo)

UTF-8 encoding: E5 8D 80 (3 bytes).

Hex color
#005340
RGB(0, 83, 64)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.83.64.

Address
0.0.83.64
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.83.64

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

Position in π

The digit sequence 21312 first appears in π at position 127,047 of the decimal expansion (the 127,047ordinal-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.