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Number

881

881 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Cousin Prime Deficient Number Evil Number Flippable Happy Number Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Historical context — 881 AD

Calendar year

Year 881 (DCCCLXXXI) was a common year starting on Sunday of the Julian calendar.

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Historical context — 881 BC

Decade

This article concerns the period 889 BC – 880 BC.

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Year facts

Year type: Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
Days in year: 365
ISO weeks: 52
Started on: Wednesday
January 1, 881
Ended on: Wednesday
December 31, 881
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 880s
880–889
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,145
1145 years before 2026.

In other calendars

Hebrew: 4641 / 4642 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 267 / 268 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Metal zodiac:Ox
Sexagenary cycle position 38 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1424 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 259 / 260 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 873 / 874 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 803 / 802 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 17
Digit product: 64
Digital root: 8
Palindrome: No
Bit width: 10 bits
Reversed: 188
Flips to (rotate 180°): 188
Recamán's sequence: a(765) = 881
Square (n²): 776,161
Cube (n³): 683,797,841
Divisor count: 2
σ(n) — sum of divisors: 882
φ(n) — Euler's totient: 880

Primality

881 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 881

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 881)

1 × 881

First multiples

881 · 1,762 (double) · 2,643 · 3,524 · 4,405 · 5,286 · 6,167 · 7,048 · 7,929 · 8,810

Sums & aliquot sequence

As a sum of two squares: 16² + 25²

As consecutive integers: 440 + 441

Representations

In words: eight hundred eighty-one
Ordinal: 881st
Roman numeral: DCCCLXXXI
Binary: 1101110001
Octal: 1561
Hexadecimal: 0x371
Base64: A3E=
One's complement: 64,654 (16-bit)

In other bases

ternary (3) 1012122

quaternary (4) 31301

quinary (5) 12011

senary (6) 4025

septenary (7) 2366

nonary (9) 1178

undecimal (11) 731

duodecimal (12) 615

tridecimal (13) 52a

tetradecimal (14) 46d

pentadecimal (15) 3db

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ωπαʹ
Mayan (base 20): 𝋢·𝋤·𝋡
Chinese: 八百八十一
Chinese (financial): 捌佰捌拾壹

In other modern scripts

Eastern Arabic ٨٨١ Devanagari ८८१ Bengali ৮৮১ Tamil ௮௮௧ Thai ๘๘๑ Tibetan ༨༨༡ Khmer ៨៨១ Lao ໘໘໑ Burmese ၈၈၁

Digit at this position in famous constants

π — Pi (π): Digit 881 = 3
e — Euler's number (e): Digit 881 = 1
φ — Golden ratio (φ): Digit 881 = 6
√2 — Pythagoras's (√2): Digit 881 = 2
ln 2 — Natural log of 2: Digit 881 = 5
γ — Euler-Mascheroni (γ): Digit 881 = 0

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 877 (gap of 4)
Next prime: 883 (gap of 2)

Pair status: twin with 883, cousin with 877.

Unicode codepoint

ͱ

Greek Small Letter Heta

U+0371

Lowercase letter (Ll)

UTF-8 encoding: CD B1 (2 bytes).

Lookup U+0371 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000371

RGB(0, 3, 113)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.113.

Address: 0.0.3.113
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.113

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