number.wiki
Number

818

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

Deficient Number Flippable Happy Number Odious Number Palindrome Pernicious Number Recamán's Sequence Semiprime Squarefree Strobogrammatic Year

Historical context — 818 AD

Calendar year

Year 818 (DCCCXVIII) was a common year starting on Friday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

Historical context — 818 BC

Decade

This article concerns the period 819 BC – 810 BC.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →

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
Monday
January 1, 818
Ended on
Monday
December 31, 818
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
1,208
1208 years before 2026.

In other calendars

Hebrew
4578 / 4579 AM
Rosh Hashanah falls in September/October.
Islamic Hijri
202 / 203 AH
Lunar calendar; year spans differ from Gregorian.
Chinese
Year of the zodiac:Earth zodiac:Dog
Sexagenary cycle position 35 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
1361 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri
196 / 197 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian
810 / 811 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
740 / 739 Saka
Indian national calendar; year starts in March.

Properties

Parity
Even
Digit count
3
Digit sum
17
Digit product
64
Digital root
8
Palindrome
Yes
Bit width
10 bits
Recamán's sequence
a(2,112) = 818
Square (n²)
669,124
Cube (n³)
547,343,432
Divisor count
4
σ(n) — sum of divisors
1,230
φ(n) — Euler's totient
408
Sum of prime factors
411

Primality

Prime factorization: 2 × 409

Nearest primes: 811 (−7) · 821 (+3)

Divisors & multiples

All divisors (4)
1 · 2 · 409 (half) · 818
Aliquot sum (sum of proper divisors): 412
Factor pairs (a × b = 818)
1 × 818
2 × 409
First multiples
818 · 1,636 (double) · 2,454 · 3,272 · 4,090 · 4,908 · 5,726 · 6,544 · 7,362 · 8,180

Sums & aliquot sequence

As a sum of two squares: 17² + 23²
As consecutive integers: 203 + 204 + 205 + 206
Aliquot sequence: 818 412 316 244 190 170 154 134 70 74 40 50 43 1 0 — terminates at zero

Representations

In words
eight hundred eighteen
Ordinal
818th
Roman numeral
DCCCXVIII
Binary
1100110010
Octal
1462
Hexadecimal
0x332
Base64
AzI=
One's complement
64,717 (16-bit)
In other bases
ternary (3) 1010022
quaternary (4) 30302
quinary (5) 11233
senary (6) 3442
septenary (7) 2246
nonary (9) 1108
undecimal (11) 684
duodecimal (12) 582
tridecimal (13) 4ac
tetradecimal (14) 426
pentadecimal (15) 398

Historical numeral systems

Babylonian (base 60)
𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
ωιηʹ
Mayan (base 20)
𝋢·𝋠·𝋲
Chinese
八百一十八
Chinese (financial)
捌佰壹拾捌
In other modern scripts
Eastern Arabic ٨١٨ Devanagari ८१८ Bengali ৮১৮ Tamil ௮௧௮ Thai ๘๑๘ Tibetan ༨༡༨ Khmer ៨១៨ Lao ໘໑໘ Burmese ၈၁၈

Digit at this position in famous constants

π — Pi (π)
Digit 818 = 3
e — Euler's number (e)
Digit 818 = 0
φ — Golden ratio (φ)
Digit 818 = 1
√2 — Pythagoras's (√2)
Digit 818 = 4
ln 2 — Natural log of 2
Digit 818 = 1
γ — Euler-Mascheroni (γ)
Digit 818 = 8

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 818, here are decompositions:

  • 7 + 811 = 818
  • 31 + 787 = 818
  • 61 + 757 = 818
  • 67 + 751 = 818
  • 79 + 739 = 818
  • 109 + 709 = 818
  • 127 + 691 = 818
  • 157 + 661 = 818

Showing the first eight; more decompositions exist.

Unicode codepoint
̲
Combining Low Line
U+0332
Non-spacing mark (Mn)

UTF-8 encoding: CC B2 (2 bytes).

Hex color
#000332
RGB(0, 3, 50)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.50.

Address
0.0.3.50
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.3.50

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

NANP area code 818

The number 818 is an active NANP area code (North American Numbering Plan).

Primary area
San Fernando Valley
Region
California
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.

Calculator-display word

Type 818 on a seven-segment calculator, flip it 180°, and the display reads:

BIB

A staple of calculator humor since pocket calculators put digits in front of bored students.