813
813 is a composite number, odd, a calendar year.
Historical context — 813 AD
Calendar year
813 (DCCCXIII) was a common year starting on Saturday of the Julian calendar, the 813th year of the Common Era (CE) and Anno Domini (AD) designations, the 813th year of the 1st millennium, the 13th year of the 9th century, and the 4th year of the 810s decade.
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Historical context — 813 BC
Decade
This article concerns the period 819 BC – 810 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
-
Tuesday
January 1, 813
- Ended on
-
Tuesday
December 31, 813
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
810s
810–819
- Century
-
9th century
801–900
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,213
1213 years before 2026.
In other calendars
- Hebrew
-
4573 / 4574 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
197 / 198 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Water zodiac:Snake
Sexagenary cycle position 30 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
1356 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
191 / 192 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
805 / 806 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
735 / 734 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 3 × 271
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- eight hundred thirteen
- Ordinal
- 813th
- Roman numeral
- DCCCXIII
- Binary
- 1100101101
- Octal
- 1455
- Hexadecimal
- 0x32D
- Base64
- Ay0=
- One's complement
- 64,722 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓏺𓏺𓏺
- Greek (Milesian)
- ωιγʹ
- Mayan (base 20)
- 𝋢·𝋠·𝋭
- Chinese
- 八百一十三
- Chinese (financial)
- 捌佰壹拾參
Digit at this position in famous constants
- π — Pi (π)
- Digit 813 = 4
- e — Euler's number (e)
- Digit 813 = 2
- φ — Golden ratio (φ)
- Digit 813 = 8
- √2 — Pythagoras's (√2)
- Digit 813 = 7
- ln 2 — Natural log of 2
- Digit 813 = 1
- γ — Euler-Mascheroni (γ)
- Digit 813 = 1
Also seen as
UTF-8 encoding: CC AD (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.45.
- Address
- 0.0.3.45
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.3.45
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 813 is an active NANP area code (North American Numbering Plan).
- Primary area
- Tampa
- Region
- Florida
- 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.