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Number

1,818

1,818 is a composite number, even, a calendar year.

Abundant Number Evil Number Flippable Gapful Number Happy Number Harshad / Niven Recamán's Sequence Self Number Semiperfect Number Year

Notable events — 1818 AD

  1. Oct 20 The Anglo-American Convention sets the US-Canada border along the 49th parallel.
  2. Dec 3 Illinois becomes the 21st US state.
  3. Feb 12 Chile formally declares independence at Talca.
  4. Mar 24 Lord Byron publishes Childe Harold's Pilgrimage Canto IV.
  5. Jan 1 Mary Shelley anonymously publishes Frankenstein.

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
53
Long year: contains 53 ISO weeks.
Started on
Thursday
January 1, 1818
Ended on
Thursday
December 31, 1818
Friday the 13ths
3
3 Friday the 13ths this year.
Easter Sunday
March 22
Sunday, March 22, 1818
Decade
1810s
1810–1819
Century
19th century
1801–1900
Millennium
2nd millennium
1001–2000
Years ago
208
208 years before 2026.

In other calendars

Hebrew
5578 / 5579 AM
Rosh Hashanah falls in September/October.
Islamic Hijri
1233 / 1234 AH
Lunar calendar; year spans differ from Gregorian.
Chinese
Year of the zodiac:Earth zodiac:Tiger
Sexagenary cycle position 15 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
2361 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri
1196 / 1197 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian
1810 / 1811 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
1740 / 1739 Saka
Indian national calendar; year starts in March.

Properties

Parity
Even
Digit count
4
Digit sum
18
Digit product
64
Digital root
9
Palindrome
No
Bit width
11 bits
Reversed
8,181
Flips to (rotate 180°)
8,181
Recamán's sequence
a(459) = 1,818
Square (n²)
3,305,124
Cube (n³)
6,008,715,432
Divisor count
12
σ(n) — sum of divisors
3,978
φ(n) — Euler's totient
600
Sum of prime factors
109

Primality

Prime factorization: 2 × 3 2 × 101

Nearest primes: 1,811 (−7) · 1,823 (+5)

Divisors & multiples

All divisors (12)
1 · 2 · 3 · 6 · 9 · 18 · 101 · 202 · 303 · 606 · 909 (half) · 1818
Aliquot sum (sum of proper divisors): 2,160
Factor pairs (a × b = 1,818)
1 × 1818
2 × 909
3 × 606
6 × 303
9 × 202
18 × 101
First multiples
1,818 · 3,636 (double) · 5,454 · 7,272 · 9,090 · 10,908 · 12,726 · 14,544 · 16,362 · 18,180

Sums & aliquot sequence

As a sum of two squares: 27² + 33²
As consecutive integers: 605 + 606 + 607 453 + 454 + 455 + 456 198 + 199 + … + 206 146 + 147 + … + 157
Aliquot sequence: 1,818 2,160 5,280 12,864 21,680 28,912 31,848 47,832 71,808 148,512 359,520 946,848 1,895,712 4,539,360 12,180,336 23,781,648 44,267,568 — unresolved within range

Representations

In words
one thousand eight hundred eighteen
Ordinal
1818th
Roman numeral
MDCCCXVIII
Binary
11100011010
Octal
3432
Hexadecimal
0x71A
Base64
Bxo=
One's complement
63,717 (16-bit)
In other bases
ternary (3) 2111100
quaternary (4) 130122
quinary (5) 24233
senary (6) 12230
septenary (7) 5205
nonary (9) 2440
undecimal (11) 1403
duodecimal (12) 1076
tridecimal (13) a9b
tetradecimal (14) 93c
pentadecimal (15) 813

Historical numeral systems

Babylonian (base 60)
𒌋𒌋𒌋 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
͵αωιηʹ
Mayan (base 20)
𝋤·𝋪·𝋲
Chinese
一千八百一十八
Chinese (financial)
壹仟捌佰壹拾捌
In other modern scripts
Eastern Arabic ١٨١٨ Devanagari १८१८ Bengali ১৮১৮ Tamil ௧௮௧௮ Thai ๑๘๑๘ Tibetan ༡༨༡༨ Khmer ១៨១៨ Lao ໑໘໑໘ Burmese ၁၈၁၈

Digit at this position in famous constants

π — Pi (π)
Digit 1,818 = 0
e — Euler's number (e)
Digit 1,818 = 2
φ — Golden ratio (φ)
Digit 1,818 = 9
√2 — Pythagoras's (√2)
Digit 1,818 = 3
ln 2 — Natural log of 2
Digit 1,818 = 4
γ — Euler-Mascheroni (γ)
Digit 1,818 = 9

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1818, here are decompositions:

  • 7 + 1811 = 1818
  • 17 + 1801 = 1818
  • 29 + 1789 = 1818
  • 31 + 1787 = 1818
  • 41 + 1777 = 1818
  • 59 + 1759 = 1818
  • 71 + 1747 = 1818
  • 97 + 1721 = 1818

Showing the first eight; more decompositions exist.

Unicode codepoint
ܚ
Syriac Letter Heth
U+071A
Other letter (Lo)

UTF-8 encoding: DC 9A (2 bytes).

Hex color
#00071A
RGB(0, 7, 26)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.26.

Address
0.0.7.26
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.7.26

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

Possible US bank routing number

This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.

Routing number
000001818
Federal Reserve
United States Government

Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.

Position in π

The digit sequence 1818 first appears in π at position 1,572 of the decimal expansion (the 1,572ordinal-suffix:nd 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.