1,806
1,806 is a composite number, even, a calendar year.
Notable events — 1806 AD
- Jul 12 Napoleon establishes the Confederation of the Rhine.
- Aug 6 Francis II abdicates as Holy Roman Emperor, ending the millennium-old empire.
- Oct 14 Napoleon crushes Prussia at Jena-Auerstedt.
- Nov 21 Napoleon issues the Berlin Decree initiating the Continental System.
- Sep 23 The Lewis and Clark expedition returns to St. Louis.
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
-
Wednesday
January 1, 1806
- Ended on
-
Wednesday
December 31, 1806
- Friday the 13ths
-
1
One Friday the 13th this year.
- Easter Sunday
-
April 6
Sunday, April 6, 1806
- Decade
-
1800s
1800–1809
- Century
-
19th century
1801–1900
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
220
220 years before 2026.
In other calendars
- Hebrew
-
5566 / 5567 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1220 / 1221 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Fire zodiac:Tiger
Sexagenary cycle position 3 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2349 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1184 / 1185 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1798 / 1799 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1728 / 1727 Saka
Indian national calendar; year starts in March.
Properties
- Parity
- Even
- Digit count
- 4
- Digit sum
- 15
- Digit product
- 0
- Digital root
- 6
- Palindrome
- No
- Bit width
- 11 bits
- Reversed
- 6,081
- Flips to (rotate 180°)
- 9,081
- Recamán's sequence
- a(16,087) = 1,806
- Square (n²)
- 3,261,636
- Cube (n³)
- 5,890,514,616
- Divisor count
- 16
- σ(n) — sum of divisors
- 4,224
- φ(n) — Euler's totient
- 504
- Sum of prime factors
- 55
Primality
Prime factorization: 2 × 3 × 7 × 43
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand eight hundred six
- Ordinal
- 1806th
- Roman numeral
- MDCCCVI
- Binary
- 11100001110
- Octal
- 3416
- Hexadecimal
- 0x70E
- Base64
- Bw4=
- One's complement
- 63,729 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋 𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵αωϛʹ
- Mayan (base 20)
- 𝋤·𝋪·𝋦
- Chinese
- 一千八百零六
- Chinese (financial)
- 壹仟捌佰零陸
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,806 = 6
- e — Euler's number (e)
- Digit 1,806 = 8
- φ — Golden ratio (φ)
- Digit 1,806 = 5
- √2 — Pythagoras's (√2)
- Digit 1,806 = 8
- ln 2 — Natural log of 2
- Digit 1,806 = 5
- γ — Euler-Mascheroni (γ)
- Digit 1,806 = 6
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1806, here are decompositions:
- 5 + 1801 = 1806
- 17 + 1789 = 1806
- 19 + 1787 = 1806
- 23 + 1783 = 1806
- 29 + 1777 = 1806
- 47 + 1759 = 1806
- 53 + 1753 = 1806
- 59 + 1747 = 1806
Showing the first eight; more decompositions exist.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.14.
- Address
- 0.0.7.14
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.7.14
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 1806 first appears in π at position 5,488 of the decimal expansion (the 5,488ordinal-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.