865
865 is a composite number, odd, a calendar year.
865 (eight hundred sixty-five) is an odd 3-digit number. It is a composite number with 4 divisors, and factors as 5 × 173. Written other ways, in Roman numerals it is DCCCLXV and in binary, 1101100001.
Interestingness
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
Primality
Prime factorization: 5 × 173
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√865 = [29; (2, 2, 3, 3, 1, 1, 1, 2, 6, 6, 2, 1, 1, 1, 3, 3, 2, 2, 58)]
Period length 19 — the block in parentheses repeats forever.
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)
- Scientific notation
- 8.65 × 10²
- As a duration
- 865 s = 14 minutes, 25 seconds
As an angle
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
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
UTF-8 encoding: CD A1 (2 bytes).
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.
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.
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.
Heard as a frequency, 865 Hz is closest to:
- Concert pitch (A4 = 440 Hz): A5 (880 Hz, -30¢)
- Scientific pitch (C4 = 256 Hz): A5 (861.1 Hz, +8¢)
- Baroque pitch (A4 = 415 Hz): A♯5 (879.4 Hz, -28¢)
Related reading
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.