Number

865

865 is a composite number, odd, a calendar year.

Arithmetic Number Deficient Number Descending Digits Odious Number Pernicious Number Recamán's Sequence Semiprime Squarefree Year

Historical context — 865 AD

Calendar year

Year 865 (DCCCLXV) was a common year starting on Monday of the Julian calendar.

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Historical context — 865 BC

Decade

This article concerns the period 869 BC – 860 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: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 865
Ended on: Thursday
December 31, 865
Friday the 13ths: 3
3 Friday the 13ths this year.
Decade: 860s
860–869
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,161
1161 years before 2026.

In other calendars

Hebrew: 4625 / 4626 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 250 / 251 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Wood zodiac:Rooster
Sexagenary cycle position 22 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1408 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 243 / 244 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 857 / 858 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 787 / 786 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 19
Digit product: 240
Digital root: 1
Palindrome: No
Bit width: 10 bits
Reversed: 568
Recamán's sequence: a(801) = 865
Square (n²): 748,225
Cube (n³): 647,214,625
Divisor count: 4
σ(n) — sum of divisors: 1,044
φ(n) — Euler's totient: 688
Sum of prime factors: 178

Primality

Prime factorization: 5 × 173

Nearest primes: 863 (−2) · 877 (+12)

Divisors & multiples

All divisors (4)

1 · 5 · 173 · 865

Aliquot sum (sum of proper divisors): 179

Factor pairs (a × b = 865)

1 × 865

5 × 173

First multiples

865 · 1,730 (double) · 2,595 · 3,460 · 4,325 · 5,190 · 6,055 · 6,920 · 7,785 · 8,650

Sums & aliquot sequence

As a sum of two squares: 9² + 28² = 17² + 24²

As consecutive integers: 432 + 433 171 + 172 + 173 + 174 + 175 82 + 83 + … + 91

Aliquot sequence: 865 → 179 → 1 → 0 — terminates at zero

Representations

In words: eight hundred sixty-five
Ordinal: 865th
Roman numeral: DCCCLXV
Binary: 1101100001
Octal: 1541
Hexadecimal: 0x361
Base64: A2E=
One's complement: 64,670 (16-bit)

In other bases

ternary (3) 1012001

quaternary (4) 31201

quinary (5) 11430

senary (6) 4001

septenary (7) 2344

nonary (9) 1161

undecimal (11) 717

duodecimal (12) 601

tridecimal (13) 517

tetradecimal (14) 45b

pentadecimal (15) 3ca

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ωξεʹ
Mayan (base 20): 𝋢·𝋣·𝋥
Chinese: 八百六十五
Chinese (financial): 捌佰陸拾伍

In other modern scripts

Eastern Arabic ٨٦٥ Devanagari ८६५ Bengali ৮৬৫ Tamil ௮௬௫ Thai ๘๖๕ Tibetan ༨༦༥ Khmer ៨៦៥ Lao ໘໖໕ Burmese ၈၆၅

Digit at this position in famous constants

π — Pi (π): Digit 865 = 8
e — Euler's number (e): Digit 865 = 1
φ — Golden ratio (φ): Digit 865 = 2
√2 — Pythagoras's (√2): Digit 865 = 2
ln 2 — Natural log of 2: Digit 865 = 9
γ — Euler-Mascheroni (γ): Digit 865 = 5

Also seen as

Unicode codepoint

Combining Double Inverted Breve

U+0361

Non-spacing mark (Mn)

UTF-8 encoding: CD A1 (2 bytes).

Lookup U+0361 on Compart ↗ Lookup on FileFormat.Info ↗

Code page identifier

Code page 865 is DOS Nordic — DOS code page for Nordic languages.

Code pages are integer identifiers used by Windows and other systems to refer to specific character encodings.

Microsoft code page reference ↗

Hex color

#000361

RGB(0, 3, 97)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.97.

Address: 0.0.3.97
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.97

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

NANP area code 865

The number 865 is an active NANP area code (North American Numbering Plan).

Primary area: Knoxville
Region: Tennessee
Country: United States

Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.

Look up area code 865 ↗