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21,670

21,670 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.).
Arithmetic Number Deficient Number Odious Number Pernicious Number Recamán's Sequence Squarefree

Properties

Parity
Even
Digit count
5
Digit sum
16
Digit product
0
Digital root
7
Palindrome
No
Bit width
15 bits
Reversed
7,612
Recamán's sequence
a(40,499) = 21,670
Square (n²)
469,588,900
Cube (n³)
10,175,991,463,000
Divisor count
16
σ(n) — sum of divisors
42,768
φ(n) — Euler's totient
7,840
Sum of prime factors
215

Primality

Prime factorization: 2 × 5 × 11 × 197

Nearest primes: 21,661 (−9) · 21,673 (+3)

Divisors & multiples

All divisors (16)
1 · 2 · 5 · 10 · 11 · 22 · 55 · 110 · 197 · 394 · 985 · 1970 · 2167 · 4334 · 10835 (half) · 21670
Aliquot sum (sum of proper divisors): 21,098
Factor pairs (a × b = 21,670)
1 × 21670
2 × 10835
5 × 4334
10 × 2167
11 × 1970
22 × 985
55 × 394
110 × 197
First multiples
21,670 · 43,340 (double) · 65,010 · 86,680 · 108,350 · 130,020 · 151,690 · 173,360 · 195,030 · 216,700

Sums & aliquot sequence

As consecutive integers: 5,416 + 5,417 + 5,418 + 5,419 4,332 + 4,333 + 4,334 + 4,335 + 4,336 1,965 + 1,966 + … + 1,975 1,074 + 1,075 + … + 1,093
Aliquot sequence: 21,670 21,098 18,646 9,326 4,666 2,336 2,326 1,166 778 392 463 1 0 — terminates at zero

Representations

In words
twenty-one thousand six hundred seventy
Ordinal
21670th
Binary
101010010100110
Octal
52246
Hexadecimal
0x54A6
Base64
VKY=
One's complement
43,865 (16-bit)
In other bases
ternary (3) 1002201121
quaternary (4) 11102212
quinary (5) 1143140
senary (6) 244154
septenary (7) 120115
nonary (9) 32647
undecimal (11) 15310
duodecimal (12) 1065a
tridecimal (13) 9b2c
tetradecimal (14) 7c7c
pentadecimal (15) 664a

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 𒁹 𒌋
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆
Greek (Milesian)
͵καχοʹ
Mayan (base 20)
𝋢·𝋮·𝋣·𝋪
Chinese
二萬一千六百七十
Chinese (financial)
貳萬壹仟陸佰柒拾
In other modern scripts
Eastern Arabic ٢١٦٧٠ Devanagari २१६७० Bengali ২১৬৭০ Tamil ௨௧௬௭௦ Thai ๒๑๖๗๐ Tibetan ༢༡༦༧༠ Khmer ២១៦៧០ Lao ໒໑໖໗໐ Burmese ၂၁၆၇၀

Digit at this position in famous constants

π — Pi (π)
Digit 21,670 = 3
e — Euler's number (e)
Digit 21,670 = 3
φ — Golden ratio (φ)
Digit 21,670 = 0
√2 — Pythagoras's (√2)
Digit 21,670 = 5
ln 2 — Natural log of 2
Digit 21,670 = 4
γ — Euler-Mascheroni (γ)
Digit 21,670 = 2

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21670, here are decompositions:

  • 23 + 21647 = 21670
  • 53 + 21617 = 21670
  • 59 + 21611 = 21670
  • 71 + 21599 = 21670
  • 83 + 21587 = 21670
  • 101 + 21569 = 21670
  • 107 + 21563 = 21670
  • 113 + 21557 = 21670

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-54A6
U+54A6
Other letter (Lo)

UTF-8 encoding: E5 92 A6 (3 bytes).

Hex color
#0054A6
RGB(0, 84, 166)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.166.

Address
0.0.84.166
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.84.166

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

Position in π

The digit sequence 21670 first appears in π at position 125,866 of the decimal expansion (the 125,866ordinal-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.