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21,512

21,512 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.).
Deficient Number Evil Number Palindrome Recamán's Sequence

Properties

Parity
Even
Digit count
5
Digit sum
11
Digit product
20
Digital root
2
Palindrome
Yes
Bit width
15 bits
Recamán's sequence
a(40,815) = 21,512
Square (n²)
462,766,144
Cube (n³)
9,955,025,289,728
Divisor count
8
σ(n) — sum of divisors
40,350
φ(n) — Euler's totient
10,752
Sum of prime factors
2,695

Primality

Prime factorization: 2 3 × 2689

Nearest primes: 21,503 (−9) · 21,517 (+5)

Divisors & multiples

All divisors (8)
1 · 2 · 4 · 8 · 2689 · 5378 · 10756 (half) · 21512
Aliquot sum (sum of proper divisors): 18,838
Factor pairs (a × b = 21,512)
1 × 21512
2 × 10756
4 × 5378
8 × 2689
First multiples
21,512 · 43,024 (double) · 64,536 · 86,048 · 107,560 · 129,072 · 150,584 · 172,096 · 193,608 · 215,120

Sums & aliquot sequence

As a sum of two squares: 14² + 146²
As consecutive integers: 1,337 + 1,338 + … + 1,352
Aliquot sequence: 21,512 18,838 9,422 6,754 4,334 2,794 1,814 910 1,106 814 554 280 440 640 890 730 602 — unresolved within range

Representations

In words
twenty-one thousand five hundred twelve
Ordinal
21512th
Binary
101010000001000
Octal
52010
Hexadecimal
0x5408
Base64
VAg=
One's complement
44,023 (16-bit)
In other bases
ternary (3) 1002111202
quaternary (4) 11100020
quinary (5) 1142022
senary (6) 243332
septenary (7) 116501
nonary (9) 32452
undecimal (11) 15187
duodecimal (12) 10548
tridecimal (13) 9a3a
tetradecimal (14) 7ba8
pentadecimal (15) 6592

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓏺𓏺
Greek (Milesian)
͵καφιβʹ
Mayan (base 20)
𝋢·𝋭·𝋯·𝋬
Chinese
二萬一千五百一十二
Chinese (financial)
貳萬壹仟伍佰壹拾貳
In other modern scripts
Eastern Arabic ٢١٥١٢ Devanagari २१५१२ Bengali ২১৫১২ Tamil ௨௧௫௧௨ Thai ๒๑๕๑๒ Tibetan ༢༡༥༡༢ Khmer ២១៥១២ Lao ໒໑໕໑໒ Burmese ၂၁၅၁၂

Digit at this position in famous constants

π — Pi (π)
Digit 21,512 = 2
e — Euler's number (e)
Digit 21,512 = 3
φ — Golden ratio (φ)
Digit 21,512 = 9
√2 — Pythagoras's (√2)
Digit 21,512 = 8
ln 2 — Natural log of 2
Digit 21,512 = 0
γ — Euler-Mascheroni (γ)
Digit 21,512 = 0

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21512, here are decompositions:

  • 13 + 21499 = 21512
  • 19 + 21493 = 21512
  • 31 + 21481 = 21512
  • 79 + 21433 = 21512
  • 193 + 21319 = 21512
  • 199 + 21313 = 21512
  • 229 + 21283 = 21512
  • 349 + 21163 = 21512

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5408
U+5408
Other letter (Lo)

UTF-8 encoding: E5 90 88 (3 bytes).

Hex color
#005408
RGB(0, 84, 8)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.8.

Address
0.0.84.8
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.84.8

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

Position in π

The digit sequence 21512 first appears in π at position 50,306 of the decimal expansion (the 50,306ordinal-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.