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21,145

21,145 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 Semiprime Squarefree

Properties

Parity
Odd
Digit count
5
Digit sum
13
Digit product
40
Digital root
4
Palindrome
No
Bit width
15 bits
Reversed
54,112
Recamán's sequence
a(41,549) = 21,145
Square (n²)
447,111,025
Cube (n³)
9,454,162,623,625
Divisor count
4
σ(n) — sum of divisors
25,380
φ(n) — Euler's totient
16,912
Sum of prime factors
4,234

Primality

Prime factorization: 5 × 4229

Nearest primes: 21,143 (−2) · 21,149 (+4)

Divisors & multiples

All divisors (4)
1 · 5 · 4229 · 21145
Aliquot sum (sum of proper divisors): 4,235
Factor pairs (a × b = 21,145)
1 × 21145
5 × 4229
First multiples
21,145 · 42,290 (double) · 63,435 · 84,580 · 105,725 · 126,870 · 148,015 · 169,160 · 190,305 · 211,450

Sums & aliquot sequence

As a sum of two squares: 61² + 132² = 69² + 128²
As consecutive integers: 10,572 + 10,573 4,227 + 4,228 + 4,229 + 4,230 + 4,231 2,110 + 2,111 + … + 2,119
Aliquot sequence: 21,145 4,235 2,149 315 309 107 1 0 — terminates at zero

Representations

In words
twenty-one thousand one hundred forty-five
Ordinal
21145th
Binary
101001010011001
Octal
51231
Hexadecimal
0x5299
Base64
Upk=
One's complement
44,390 (16-bit)
In other bases
ternary (3) 1002000011
quaternary (4) 11022121
quinary (5) 1134040
senary (6) 241521
septenary (7) 115435
nonary (9) 32004
undecimal (11) 14983
duodecimal (12) 102a1
tridecimal (13) 9817
tetradecimal (14) 79c5
pentadecimal (15) 63ea

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵καρμεʹ
Mayan (base 20)
𝋢·𝋬·𝋱·𝋥
Chinese
二萬一千一百四十五
Chinese (financial)
貳萬壹仟壹佰肆拾伍
In other modern scripts
Eastern Arabic ٢١١٤٥ Devanagari २११४५ Bengali ২১১৪৫ Tamil ௨௧௧௪௫ Thai ๒๑๑๔๕ Tibetan ༢༡༡༤༥ Khmer ២១១៤៥ Lao ໒໑໑໔໕ Burmese ၂၁၁၄၅

Digit at this position in famous constants

π — Pi (π)
Digit 21,145 = 3
e — Euler's number (e)
Digit 21,145 = 7
φ — Golden ratio (φ)
Digit 21,145 = 0
√2 — Pythagoras's (√2)
Digit 21,145 = 6
ln 2 — Natural log of 2
Digit 21,145 = 7
γ — Euler-Mascheroni (γ)
Digit 21,145 = 6

Also seen as

Unicode codepoint
CJK Unified Ideograph-5299
U+5299
Other letter (Lo)

UTF-8 encoding: E5 8A 99 (3 bytes).

Hex color
#005299
RGB(0, 82, 153)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.82.153.

Address
0.0.82.153
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.82.153

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

Position in π

The digit sequence 21145 first appears in π at position 148,883 of the decimal expansion (the 148,883ordinal-suffix:rd 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.