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81,021

81,021 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 Happy Number Odious Number Pernicious Number Recamán's Sequence Sphenic Number Squarefree

Properties

Parity
Odd
Digit count
5
Digit sum
12
Digit product
0
Digital root
3
Palindrome
No
Bit width
17 bits
Reversed
12,018
Recamán's sequence
a(272,330) = 81,021
Square (n²)
6,564,402,441
Cube (n³)
531,854,450,172,261
Divisor count
8
σ(n) — sum of divisors
109,440
φ(n) — Euler's totient
53,312
Sum of prime factors
355

Primality

Prime factorization: 3 × 113 × 239

Nearest primes: 81,019 (−2) · 81,023 (+2)

Divisors & multiples

All divisors (8)
1 · 3 · 113 · 239 · 339 · 717 · 27007 · 81021
Aliquot sum (sum of proper divisors): 28,419
Factor pairs (a × b = 81,021)
1 × 81021
3 × 27007
113 × 717
239 × 339
First multiples
81,021 · 162,042 (double) · 243,063 · 324,084 · 405,105 · 486,126 · 567,147 · 648,168 · 729,189 · 810,210

Sums & aliquot sequence

As consecutive integers: 40,510 + 40,511 27,006 + 27,007 + 27,008 13,501 + 13,502 + 13,503 + 13,504 + 13,505 + 13,506 661 + 662 + … + 773
Aliquot sequence: 81,021 28,419 9,477 5,825 1,429 1 0 — terminates at zero

Representations

In words
eighty-one thousand twenty-one
Ordinal
81021st
Binary
10011110001111101
Octal
236175
Hexadecimal
0x13C7D
Base64
ATx9
One's complement
4,294,886,274 (32-bit)
In other bases
ternary (3) 11010010210
quaternary (4) 103301331
quinary (5) 10043041
senary (6) 1423033
septenary (7) 455133
nonary (9) 133123
undecimal (11) 55966
duodecimal (12) 3aa79
tridecimal (13) 2ab55
tetradecimal (14) 21753
pentadecimal (15) 19016

Historical numeral systems

Babylonian (base 60)
𒌋𒌋𒁹𒁹 𒌋𒌋𒌋 𒌋𒌋𒁹
Egyptian hieroglyphic
𓂍𓂍𓂍𓂍𓂍𓂍𓂍𓂍𓆼𓎆𓎆𓏺
Greek (Milesian)
͵πακαʹ
Mayan (base 20)
𝋪·𝋢·𝋫·𝋡
Chinese
八萬一千零二十一
Chinese (financial)
捌萬壹仟零貳拾壹
In other modern scripts
Eastern Arabic ٨١٠٢١ Devanagari ८१०२१ Bengali ৮১০২১ Tamil ௮௧௦௨௧ Thai ๘๑๐๒๑ Tibetan ༨༡༠༢༡ Khmer ៨១០២១ Lao ໘໑໐໒໑ Burmese ၈၁၀၂၁

Digit at this position in famous constants

π — Pi (π)
Digit 81,021 = 8
e — Euler's number (e)
Digit 81,021 = 9
φ — Golden ratio (φ)
Digit 81,021 = 6
√2 — Pythagoras's (√2)
Digit 81,021 = 9
ln 2 — Natural log of 2
Digit 81,021 = 8
γ — Euler-Mascheroni (γ)
Digit 81,021 = 8

Also seen as

Unicode codepoint
𓱽
Egyptian Hieroglyph-13C7D
U+13C7D
Other letter (Lo)

UTF-8 encoding: F0 93 B1 BD (4 bytes).

Hex color
#013C7D
RGB(1, 60, 125)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.1.60.125.

Address
0.1.60.125
Class
reserved
IPv4-mapped IPv6
::ffff:0.1.60.125

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

Position in π

The digit sequence 81021 first appears in π at position 16,555 of the decimal expansion (the 16,555ordinal-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.