831
831 is a composite number, odd, a calendar year.
Historical context — 831 AD
Calendar year
Year 831 (DCCCXXXI) was a common year starting on Sunday of the Julian calendar.
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Historical context — 831 BC
Decade
This article concerns the period 839 BC – 830 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, 831
- Ended on
-
Wednesday
December 31, 831
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
830s
830–839
- Century
-
9th century
801–900
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,195
1195 years before 2026.
In other calendars
- Hebrew
-
4591 / 4592 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
215 / 216 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Metal zodiac:Pig
Sexagenary cycle position 48 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
1374 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
209 / 210 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
823 / 824 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
753 / 752 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 3 × 277
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- eight hundred thirty-one
- Ordinal
- 831st
- Roman numeral
- DCCCXXXI
- Binary
- 1100111111
- Octal
- 1477
- Hexadecimal
- 0x33F
- Base64
- Az8=
- One's complement
- 64,704 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹
- Egyptian hieroglyphic
- 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓏺
- Greek (Milesian)
- ωλαʹ
- Mayan (base 20)
- 𝋢·𝋡·𝋫
- Chinese
- 八百三十一
- Chinese (financial)
- 捌佰參拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 831 = 5
- e — Euler's number (e)
- Digit 831 = 0
- φ — Golden ratio (φ)
- Digit 831 = 3
- √2 — Pythagoras's (√2)
- Digit 831 = 9
- ln 2 — Natural log of 2
- Digit 831 = 9
- γ — Euler-Mascheroni (γ)
- Digit 831 = 2
Also seen as
UTF-8 encoding: CC BF (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.63.
- Address
- 0.0.3.63
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.3.63
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 831 is an active NANP area code (North American Numbering Plan).
- Primary area
- Monterey / Santa Cruz
- Region
- California
- 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.