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21,091

21,091 is a composite number, odd.

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 Sphenic Number Squarefree

Properties

Parity
Odd
Digit count
5
Digit sum
13
Digit product
0
Digital root
4
Palindrome
No
Bit width
15 bits
Reversed
19,012
Recamán's sequence
a(41,657) = 21,091
Square (n²)
444,830,281
Cube (n³)
9,381,915,456,571
Divisor count
8
σ(n) — sum of divisors
25,344
φ(n) — Euler's totient
17,160
Sum of prime factors
161

Primality

Prime factorization: 7 × 23 × 131

Nearest primes: 21,089 (−2) · 21,101 (+10)

Divisors & multiples

All divisors (8)
1 · 7 · 23 · 131 · 161 · 917 · 3013 · 21091
Aliquot sum (sum of proper divisors): 4,253
Factor pairs (a × b = 21,091)
1 × 21091
7 × 3013
23 × 917
131 × 161
First multiples
21,091 · 42,182 (double) · 63,273 · 84,364 · 105,455 · 126,546 · 147,637 · 168,728 · 189,819 · 210,910

Sums & aliquot sequence

As consecutive integers: 10,545 + 10,546 3,010 + 3,011 + … + 3,016 1,500 + 1,501 + … + 1,513 906 + 907 + … + 928
Aliquot sequence: 21,091 4,253 1 0 — terminates at zero

Representations

In words
twenty-one thousand ninety-one
Ordinal
21091st
Binary
101001001100011
Octal
51143
Hexadecimal
0x5263
Base64
UmM=
One's complement
44,444 (16-bit)
In other bases
ternary (3) 1001221011
quaternary (4) 11021203
quinary (5) 1133331
senary (6) 241351
septenary (7) 115330
nonary (9) 31834
undecimal (11) 14934
duodecimal (12) 10257
tridecimal (13) 97a5
tetradecimal (14) 7987
pentadecimal (15) 63b1

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹 𒌋𒌋𒌋𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian)
͵καϟαʹ
Mayan (base 20)
𝋢·𝋬·𝋮·𝋫
Chinese
二萬一千零九十一
Chinese (financial)
貳萬壹仟零玖拾壹
In other modern scripts
Eastern Arabic ٢١٠٩١ Devanagari २१०९१ Bengali ২১০৯১ Tamil ௨௧௦௯௧ Thai ๒๑๐๙๑ Tibetan ༢༡༠༩༡ Khmer ២១០៩១ Lao ໒໑໐໙໑ Burmese ၂၁၀၉၁

Digit at this position in famous constants

π — Pi (π)
Digit 21,091 = 3
e — Euler's number (e)
Digit 21,091 = 2
φ — Golden ratio (φ)
Digit 21,091 = 9
√2 — Pythagoras's (√2)
Digit 21,091 = 5
ln 2 — Natural log of 2
Digit 21,091 = 3
γ — Euler-Mascheroni (γ)
Digit 21,091 = 7

Also seen as

Unicode codepoint
CJK Unified Ideograph-5263
U+5263
Other letter (Lo)

UTF-8 encoding: E5 89 A3 (3 bytes).

Hex color
#005263
RGB(0, 82, 99)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.99.

Address
0.0.82.99
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.99

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

Position in π

The digit sequence 21091 first appears in π at position 32,490 of the decimal expansion (the 32,490ordinal-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.