Number

1,808

1,808 is a composite number, even, a calendar year.

1,808 (one thousand eight hundred eight) is an even 4-digit number. It is a composite number with 10 divisors, and factors as 2⁴ × 113. Written other ways, in Roman numerals it is MDCCCVIII and in binary, 11100010000.

Deficient Number Evil Number Flippable Happy Number Recamán's Sequence Year

Interestingness

★ ☆ ☆ ☆ ☆

3 notable facts · grade F

1,796 1,797 1,798 1,799 1,800 1,801 1,802 1,803 1,804 1,805 1,806 1,807 1,808 1,809 1,810 1,811 1,812 1,813 1,814 1,815 1,816 1,817 1,818 1,819 1,820

less more

Notable events — 1808 AD

Jan 1 The US ban on importing slaves takes effect.
May 2 Spaniards rise against French occupation; "the Second of May" is depicted by Goya.
Jun 6 Joseph Bonaparte becomes king of Spain.
Sep 27 The Congress of Erfurt reaffirms the Tilsit alliance.
Dec 22 Beethoven premieres his Fifth and Sixth Symphonies in Vienna.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

Year facts

Year type: Leap year
Divisible by 4 and not by 100; February has 29 days.
Days in year: 366
ISO weeks: 52
Started on: Friday
January 1, 1808
Ended on: Saturday
December 31, 1808
Friday the 13ths: 1
One Friday the 13th this year.
Easter Sunday: April 17
Sunday, April 17, 1808
Decade: 1800s
1800–1809
Century: 19th century
1801–1900
Millennium: 2nd millennium
1001–2000
Years ago: 218
218 years before 2026.
US presidential election: Yes
US holds a presidential election in years divisible by 4 starting from 1788.

In other calendars

Hebrew: 5568 / 5569 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1222 / 1223 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Earth zodiac:Dragon
Sexagenary cycle position 5 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 2351 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1186 / 1187 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1800 / 1801 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1730 / 1729 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 17
Digit product: 0
Digital root: 8
Palindrome: No
Bit width: 11 bits
Reversed: 8,081
Flips to (rotate 180°): 8,081
Recamán's sequence: a(16,083) = 1,808
Square (n²): 3,268,864
Cube (n³): 5,910,106,112
Divisor count: 10
σ(n) — sum of divisors: 3,534
φ(n) — Euler's totient: 896
Sum of prime factors: 121

Primality

Prime factorization: 2 ⁴ × 113

Nearest primes: 1,801 (−7) · 1,811 (+3)

Divisors & multiples

All divisors (10)

1 · 2 · 4 · 8 · 16 · 113 · 226 · 452 · 904 (half) · 1808

Aliquot sum (sum of proper divisors): 1,726

Factor pairs (a × b = 1,808)

1 × 1808

2 × 904

4 × 452

8 × 226

16 × 113

First multiples

1,808 · 3,616 (double) · 5,424 · 7,232 · 9,040 · 10,848 · 12,656 · 14,464 · 16,272 · 18,080

Sums & aliquot sequence

As a sum of two squares: 28² + 32²

As consecutive integers: 41 + 42 + … + 72

Aliquot sequence: 1,808 → 1,726 → 866 → 436 → 334 → 170 → 154 → 134 → 70 → 74 → 40 → 50 → 43 → 1 → 0 — terminates at zero

Continued fraction of √n

√1,808 = [42; (1, 1, 11, 1, 1, 1, 4, 1, 1, 1, 11, 1, 1, 84)]

Period length 14 — the block in parentheses repeats forever.

Representations

In words: one thousand eight hundred eight
Ordinal: 1808th
Roman numeral: MDCCCVIII
Binary: 11100010000
Octal: 3420
Hexadecimal: 0x710
Base64: BxA=
One's complement: 63,727 (16-bit)
Scientific notation: 1.808 × 10³
As a duration: 1,808 s = 30 minutes, 8 seconds

In other bases

ternary (3) 2110222

quaternary (4) 130100

quinary (5) 24213

senary (6) 12212

septenary (7) 5162

nonary (9) 2428

undecimal (11) 13a4

duodecimal (12) 1068

tridecimal (13) a91

tetradecimal (14) 932

pentadecimal (15) 808

Palindromic in base 15

As an angle

1,808° = 5 × 360° + 8°

8° ≈ 0.14 rad

Compass bearing: N (north)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵αωηʹ
Mayan (base 20): 𝋤·𝋪·𝋨
Chinese: 一千八百零八
Chinese (financial): 壹仟捌佰零捌

In other modern scripts

Eastern Arabic ١٨٠٨ Devanagari १८०८ Bengali ১৮০৮ Tamil ௧௮௦௮ Thai ๑๘๐๘ Tibetan ༡༨༠༨ Khmer ១៨០៨ Lao ໑໘໐໘ Burmese ၁၈၀၈

Digit at this position in famous constants

π — Pi (π): Digit 1,808 = 9
e — Euler's number (e): Digit 1,808 = 1
φ — Golden ratio (φ): Digit 1,808 = 7
√2 — Pythagoras's (√2): Digit 1,808 = 7
ln 2 — Natural log of 2: Digit 1,808 = 2
γ — Euler-Mascheroni (γ): Digit 1,808 = 1

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1808, here are decompositions:

7 + 1801 = 1808
19 + 1789 = 1808
31 + 1777 = 1808
61 + 1747 = 1808
67 + 1741 = 1808
109 + 1699 = 1808
139 + 1669 = 1808
151 + 1657 = 1808

Showing the first eight; more decompositions exist.

Unicode codepoint

Syriac Letter Alaph

U+0710

Other letter (Lo)

UTF-8 encoding: DC 90 (2 bytes).

Lookup U+0710 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000710

RGB(0, 7, 16)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.16.

Address: 0.0.7.16
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.16

Unspecified address (0.0.0.0/8) — "this network" placeholder.

Musical pitch

Heard as a frequency, 1,808 Hz is closest to:

Concert pitch (A4 = 440 Hz): A6 (1760 Hz, +47¢ — about midway to A♯6)
Scientific pitch (C4 = 256 Hz): A♯6 (1824.6 Hz, -16¢)
Baroque pitch (A4 = 415 Hz): A♯6 (1758.7 Hz, +48¢ — about midway to B6)

Position in π

The digit sequence 1808 first appears in π at position 26,034 of the decimal expansion (the 26,034ordinal-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.

Look up 1808 on Pi Search ↗