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21,072

21,072 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 Harshad / Niven Odious Number Pernicious Number Recamán's Sequence Semiperfect Number

Properties

Parity
Even
Digit count
5
Digit sum
12
Digit product
0
Digital root
3
Palindrome
No
Bit width
15 bits
Reversed
27,012
Recamán's sequence
a(41,695) = 21,072
Square (n²)
444,029,184
Cube (n³)
9,356,582,965,248
Divisor count
20
σ(n) — sum of divisors
54,560
φ(n) — Euler's totient
7,008
Sum of prime factors
450

Primality

Prime factorization: 2 4 × 3 × 439

Nearest primes: 21,067 (−5) · 21,089 (+17)

Divisors & multiples

All divisors (20)
1 · 2 · 3 · 4 · 6 · 8 · 12 · 16 · 24 · 48 · 439 · 878 · 1317 · 1756 · 2634 · 3512 · 5268 · 7024 · 10536 (half) · 21072
Aliquot sum (sum of proper divisors): 33,488
Factor pairs (a × b = 21,072)
1 × 21072
2 × 10536
3 × 7024
4 × 5268
6 × 3512
8 × 2634
12 × 1756
16 × 1317
24 × 878
48 × 439
First multiples
21,072 · 42,144 (double) · 63,216 · 84,288 · 105,360 · 126,432 · 147,504 · 168,576 · 189,648 · 210,720

Sums & aliquot sequence

As consecutive integers: 7,023 + 7,024 + 7,025 643 + 644 + … + 674 172 + 173 + … + 267
Aliquot sequence: 21,072 33,488 49,840 84,080 111,592 127,808 125,938 62,972 73,444 79,324 79,380 210,294 310,746 320,838 412,602 412,614 518,622 — unresolved within range

Representations

In words
twenty-one thousand seventy-two
Ordinal
21072nd
Binary
101001001010000
Octal
51120
Hexadecimal
0x5250
Base64
UlA=
One's complement
44,463 (16-bit)
In other bases
ternary (3) 1001220110
quaternary (4) 11021100
quinary (5) 1133242
senary (6) 241320
septenary (7) 115302
nonary (9) 31813
undecimal (11) 14917
duodecimal (12) 10240
tridecimal (13) 978c
tetradecimal (14) 7972
pentadecimal (15) 639c

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹 𒌋𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺
Greek (Milesian)
͵καοβʹ
Mayan (base 20)
𝋢·𝋬·𝋭·𝋬
Chinese
二萬一千零七十二
Chinese (financial)
貳萬壹仟零柒拾貳
In other modern scripts
Eastern Arabic ٢١٠٧٢ Devanagari २१०७२ Bengali ২১০৭২ Tamil ௨௧௦௭௨ Thai ๒๑๐๗๒ Tibetan ༢༡༠༧༢ Khmer ២១០៧២ Lao ໒໑໐໗໒ Burmese ၂၁၀၇၂

Digit at this position in famous constants

π — Pi (π)
Digit 21,072 = 4
e — Euler's number (e)
Digit 21,072 = 2
φ — Golden ratio (φ)
Digit 21,072 = 9
√2 — Pythagoras's (√2)
Digit 21,072 = 6
ln 2 — Natural log of 2
Digit 21,072 = 4
γ — Euler-Mascheroni (γ)
Digit 21,072 = 8

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21072, here are decompositions:

  • 5 + 21067 = 21072
  • 11 + 21061 = 21072
  • 13 + 21059 = 21072
  • 41 + 21031 = 21072
  • 53 + 21019 = 21072
  • 59 + 21013 = 21072
  • 61 + 21011 = 21072
  • 71 + 21001 = 21072

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5250
U+5250
Other letter (Lo)

UTF-8 encoding: E5 89 90 (3 bytes).

Hex color
#005250
RGB(0, 82, 80)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.80.

Address
0.0.82.80
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.80

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

Position in π

The digit sequence 21072 first appears in π at position 19,257 of the decimal expansion (the 19,257ordinal-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.