1,805
1,805 is a composite number, odd, a calendar year.
Notable events — 1805 AD
- Oct 21 Nelson defeats the Franco-Spanish fleet at Trafalgar; he is killed in the battle.
- Dec 2 Napoleon decisively defeats the Russians and Austrians at Austerlitz.
- Apr 27 US Marines storm Derna in Tripoli, the first US land action overseas.
- Nov 7 Lewis and Clark reach the Pacific Ocean.
- Dec 26 The Treaty of Pressburg dissolves the Holy Roman Empire's grip on Italy.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
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, 1805
- Ended on
-
Tuesday
December 31, 1805
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Easter Sunday
-
April 14
Sunday, April 14, 1805
- Decade
-
1800s
1800–1809
- Century
-
19th century
1801–1900
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
221
221 years before 2026.
In other calendars
- Hebrew
-
5565 / 5566 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1219 / 1220 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Wood zodiac:Ox
Sexagenary cycle position 2 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2348 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1183 / 1184 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1797 / 1798 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1727 / 1726 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 5 × 19 2
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand eight hundred five
- Ordinal
- 1805th
- Roman numeral
- MDCCCV
- Binary
- 11100001101
- Octal
- 3415
- Hexadecimal
- 0x70D
- Base64
- Bw0=
- One's complement
- 63,730 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋 𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵αωεʹ
- Mayan (base 20)
- 𝋤·𝋪·𝋥
- Chinese
- 一千八百零五
- Chinese (financial)
- 壹仟捌佰零伍
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,805 = 9
- e — Euler's number (e)
- Digit 1,805 = 5
- φ — Golden ratio (φ)
- Digit 1,805 = 5
- √2 — Pythagoras's (√2)
- Digit 1,805 = 5
- ln 2 — Natural log of 2
- Digit 1,805 = 0
- γ — Euler-Mascheroni (γ)
- Digit 1,805 = 1
Also seen as
UTF-8 encoding: DC 8D (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.13.
- Address
- 0.0.7.13
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.7.13
Unspecified address (0.0.0.0/8) — "this network" placeholder.
This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.
Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.
The digit sequence 1805 first appears in π at position 10,959 of the decimal expansion (the 10,959ordinal-suffix:th digit after the integer 3).
Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.