Number

823

823 is a prime, odd, a calendar year.

Arithmetic Number Cousin Prime Deficient Number Odious Number Pernicious Number Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Historical context — 823 AD

Calendar year

Year 823 (DCCCXXIII) was a common year starting on Thursday of the Julian calendar.

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Historical context — 823 BC

Decade

This article concerns the period 829 BC – 820 BC.

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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: Sunday
January 1, 823
Ended on: Sunday
December 31, 823
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 820s
820–829
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,203
1203 years before 2026.

In other calendars

Hebrew: 4583 / 4584 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 207 / 208 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Water zodiac:Rabbit
Sexagenary cycle position 40 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1366 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 201 / 202 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 815 / 816 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 745 / 744 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 13
Digit product: 48
Digital root: 4
Palindrome: No
Bit width: 10 bits
Reversed: 328
Recamán's sequence: a(2,102) = 823
Square (n²): 677,329
Cube (n³): 557,441,767
Divisor count: 2
σ(n) — sum of divisors: 824
φ(n) — Euler's totient: 822

Primality

823 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 823

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 823)

1 × 823

First multiples

823 · 1,646 (double) · 2,469 · 3,292 · 4,115 · 4,938 · 5,761 · 6,584 · 7,407 · 8,230

Sums & aliquot sequence

As consecutive integers: 411 + 412

Representations

In words: eight hundred twenty-three
Ordinal: 823rd
Roman numeral: DCCCXXIII
Binary: 1100110111
Octal: 1467
Hexadecimal: 0x337
Base64: Azc=
One's complement: 64,712 (16-bit)

In other bases

ternary (3) 1010111

quaternary (4) 30313

quinary (5) 11243

senary (6) 3451

septenary (7) 2254

nonary (9) 1114

undecimal (11) 689

duodecimal (12) 587

tridecimal (13) 4b4

tetradecimal (14) 42b

pentadecimal (15) 39d

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓏺𓏺𓏺
Greek (Milesian): ωκγʹ
Mayan (base 20): 𝋢·𝋡·𝋣
Chinese: 八百二十三
Chinese (financial): 捌佰貳拾參

In other modern scripts

Eastern Arabic ٨٢٣ Devanagari ८२३ Bengali ৮২৩ Tamil ௮௨௩ Thai ๘๒๓ Tibetan ༨༢༣ Khmer ៨២៣ Lao ໘໒໓ Burmese ၈၂၃

Digit at this position in famous constants

π — Pi (π): Digit 823 = 2
e — Euler's number (e): Digit 823 = 8
φ — Golden ratio (φ): Digit 823 = 0
√2 — Pythagoras's (√2): Digit 823 = 6
ln 2 — Natural log of 2: Digit 823 = 8
γ — Euler-Mascheroni (γ): Digit 823 = 0

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 821 (gap of 2)
Next prime: 827 (gap of 4)

Pair status: twin with 821, cousin with 827.

Unicode codepoint

Combining Short Solidus Overlay

U+0337

Non-spacing mark (Mn)

UTF-8 encoding: CC B7 (2 bytes).

Lookup U+0337 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000337

RGB(0, 3, 55)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.55.

Address: 0.0.3.55
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.55

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