Live analysis

21,006

21,006 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.).

21,006 (twenty-one thousand six) is an even 5-digit number. It is a composite number with 16 divisors, and factors as 2 × 3³ × 389. Its proper divisors sum to 25,794, more than the number itself, making it an abundant number. Written other ways, in hexadecimal, 0x520E.

Abundant Number Arithmetic Number Evil Number Harshad / Niven Recamán's Sequence Semiperfect Number

Interestingness

★ ★ ☆ ☆ ☆

4 notable facts · grade D

20,994 20,995 20,996 20,997 20,998 20,999 21,000 21,001 21,002 21,003 21,004 21,005 21,006 21,007 21,008 21,009 21,010 21,011 21,012 21,013 21,014 21,015 21,016 21,017 21,018

less more

Properties

Parity: Even
Digit count: 5
Digit sum: 9
Digit product: 0
Digital root: 9
Palindrome: No
Bit width: 15 bits
Reversed: 60,012
Recamán's sequence: a(41,827) = 21,006
Square (n²): 441,252,036
Cube (n³): 9,268,940,268,216
Divisor count: 16
σ(n) — sum of divisors: 46,800
φ(n) — Euler's totient: 6,984
Sum of prime factors: 400

Primality

Prime factorization: 2 × 3 ³ × 389

Nearest primes: 21,001 (−5) · 21,011 (+5)

Divisors & multiples

All divisors (16)

1 · 2 · 3 · 6 · 9 · 18 · 27 · 54 · 389 · 778 · 1167 · 2334 · 3501 · 7002 · 10503 (half) · 21006

Aliquot sum (sum of proper divisors): 25,794

Factor pairs (a × b = 21,006)

1 × 21006

2 × 10503

3 × 7002

6 × 3501

9 × 2334

18 × 1167

27 × 778

54 × 389

First multiples

21,006 · 42,012 (double) · 63,018 · 84,024 · 105,030 · 126,036 · 147,042 · 168,048 · 189,054 · 210,060

Sums & aliquot sequence

As consecutive integers: 7,001 + 7,002 + 7,003 5,250 + 5,251 + 5,252 + 5,253 2,330 + 2,331 + … + 2,338 1,745 + 1,746 + … + 1,756

Aliquot sequence: 21,006 → 25,794 → 30,132 → 51,404 → 40,324 → 34,520 → 43,240 → 60,440 → 75,640 → 102,920 → 139,000 → 188,600 → 280,120 → 367,880 → 510,160 → 846,896 → 835,288 — unresolved within range

Continued fraction of √n

√21,006 = [144; (1, 14, 3, 1, 5, 1, 2, 5, 57, 1, 3, 1, 2, 3, 1, 31, 2, 3, 2, 11, 6, 2, 1, 4, …)]

Period length 48 — the block in parentheses repeats forever.

Representations

In words: twenty-one thousand six
Ordinal: 21006th
Binary: 101001000001110
Octal: 51016
Hexadecimal: 0x520E
Base64: Ug4=
One's complement: 44,529 (16-bit)
Scientific notation: 2.1006 × 10⁴
As a duration: 21,006 s = 5 hours, 50 minutes, 6 seconds

In other bases

ternary (3) 1001211000

quaternary (4) 11020032

quinary (5) 1133011

senary (6) 241130

septenary (7) 115146

nonary (9) 31730

undecimal (11) 14867

duodecimal (12) 101a6

tridecimal (13) 973b

tetradecimal (14) 7926

pentadecimal (15) 6356

As an angle

21,006° = 58 × 360° + 126°

126° ≈ 2.199 rad

Compass bearing: SE (southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋 𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓂍𓂍𓆼𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵καϛʹ
Mayan (base 20): 𝋢·𝋬·𝋪·𝋦
Chinese: 二萬一千零六
Chinese (financial): 貳萬壹仟零陸

In other modern scripts

Eastern Arabic ٢١٠٠٦ Devanagari २१००६ Bengali ২১০০৬ Tamil ௨௧௦௦௬ Thai ๒๑๐๐๖ Tibetan ༢༡༠༠༦ Khmer ២១០០៦ Lao ໒໑໐໐໖ Burmese ၂၁၀၀၆

Digit at this position in famous constants

π — Pi (π): Digit 21,006 = 0
e — Euler's number (e): Digit 21,006 = 9
φ — Golden ratio (φ): Digit 21,006 = 1
√2 — Pythagoras's (√2): Digit 21,006 = 3
ln 2 — Natural log of 2: Digit 21,006 = 9
γ — Euler-Mascheroni (γ): Digit 21,006 = 4

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21006, here are decompositions:

5 + 21001 = 21006
23 + 20983 = 21006
43 + 20963 = 21006
47 + 20959 = 21006
59 + 20947 = 21006
67 + 20939 = 21006
103 + 20903 = 21006
107 + 20899 = 21006

Showing the first eight; more decompositions exist.

Unicode codepoint

刎

CJK Unified Ideograph-520E

U+520E

Other letter (Lo)

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

Lookup U+520E on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00520E

RGB(0, 82, 14)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.14.

Address: 0.0.82.14
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.82.14

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

Position in π

The digit sequence 21006 first appears in π at position 3,479 of the decimal expansion (the 3,479ordinal-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.

Look up 21006 on Pi Search ↗