Number

804

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

804 (eight hundred four) is an even 3-digit number. It is a composite number with 12 divisors, and factors as 2² × 3 × 67. Its proper divisors sum to 1,100, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is DCCCIV and in binary, 1100100100.

Abundant Number Cube-Free Evil Number Harshad / Niven Moran Number Recamán's Sequence Refactorable Number Self Number Semiperfect Number Year

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816

less more

Historical context — 804 AD

Calendar year

Year 804 (DCCCIV) was a leap year starting on Monday of the Julian calendar.

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

Historical context — 804 BC

Decade

This article concerns the period 809 BC – 800 BC.

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

Year facts

Year type: Leap year
Divisible by 4 and not by 100; February has 29 days.
Days in year: 366
ISO weeks: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 804
Ended on: Friday
December 31, 804
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 800s
800–809
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,222
1222 years before 2026.

In other calendars

Hebrew: 4564 / 4565 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 188 / 189 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Wood zodiac:Monkey
Sexagenary cycle position 21 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1347 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 182 / 183 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 796 / 797 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 726 / 725 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 12
Digit product: 0
Digital root: 3
Palindrome: No
Bit width: 10 bits
Reversed: 408
Recamán's sequence: a(2,140) = 804
Square (n²): 646,416
Cube (n³): 519,718,464
Divisor count: 12
σ(n) — sum of divisors: 1,904
φ(n) — Euler's totient: 264
Sum of prime factors: 74

Primality

Prime factorization: 2 ² × 3 × 67

Nearest primes: 797 (−7) · 809 (+5)

Divisors & multiples

All divisors (12)

1 · 2 · 3 · 4 · 6 · 12 · 67 · 134 · 201 · 268 · 402 (half) · 804

Aliquot sum (sum of proper divisors): 1,100

Factor pairs (a × b = 804)

1 × 804

2 × 402

3 × 268

4 × 201

6 × 134

12 × 67

First multiples

804 · 1,608 (double) · 2,412 · 3,216 · 4,020 · 4,824 · 5,628 · 6,432 · 7,236 · 8,040

Sums & aliquot sequence

As consecutive integers: 267 + 268 + 269 97 + 98 + … + 104 22 + 23 + … + 45

Aliquot sequence: 804 → 1,100 → 1,504 → 1,520 → 2,200 → 3,380 → 4,306 → 2,156 → 2,632 → 3,128 → 3,352 → 2,948 → 2,764 → 2,080 → 3,212 → 3,004 → 2,260 — unresolved within range

Continued fraction of √n

√804 = [28; (2, 1, 4, 2, 18, 2, 4, 1, 2, 56)]

Period length 10 — the block in parentheses repeats forever.

Representations

In words: eight hundred four
Ordinal: 804th
Roman numeral: DCCCIV
Binary: 1100100100
Octal: 1444
Hexadecimal: 0x324
Base64: AyQ=
One's complement: 64,731 (16-bit)
Scientific notation: 8.04 × 10²
As a duration: 804 s = 13 minutes, 24 seconds

In other bases

ternary (3) 1002210

quaternary (4) 30210

quinary (5) 11204

senary (6) 3420

septenary (7) 2226

nonary (9) 1083

undecimal (11) 671

duodecimal (12) 570

tridecimal (13) 49b

tetradecimal (14) 416

pentadecimal (15) 389

As an angle

804° = 2 × 360° + 84°

84° ≈ 1.466 rad

Compass bearing: E (east)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺
Greek (Milesian): ωδʹ
Mayan (base 20): 𝋢·𝋠·𝋤
Chinese: 八百零四
Chinese (financial): 捌佰零肆

In other modern scripts

Eastern Arabic ٨٠٤ Devanagari ८०४ Bengali ৮০৪ Tamil ௮௦௪ Thai ๘๐๔ Tibetan ༨༠༤ Khmer ៨០៤ Lao ໘໐໔ Burmese ၈၀၄

Digit at this position in famous constants

π — Pi (π): Digit 804 = 2
e — Euler's number (e): Digit 804 = 8
φ — Golden ratio (φ): Digit 804 = 2
√2 — Pythagoras's (√2): Digit 804 = 3
ln 2 — Natural log of 2: Digit 804 = 2
γ — Euler-Mascheroni (γ): Digit 804 = 6

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 804, here are decompositions:

7 + 797 = 804
17 + 787 = 804
31 + 773 = 804
43 + 761 = 804
47 + 757 = 804
53 + 751 = 804
61 + 743 = 804
71 + 733 = 804

Showing the first eight; more decompositions exist.

Unicode codepoint

Combining Diaeresis Below

U+0324

Non-spacing mark (Mn)

UTF-8 encoding: CC A4 (2 bytes).

Lookup U+0324 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000324

RGB(0, 3, 36)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.36.

Address: 0.0.3.36
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.36

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

NANP area code 804

The number 804 is an active NANP area code (North American Numbering Plan).

Primary area: Richmond
Region: Virginia
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.

Look up area code 804 ↗

Calculator-display word

Type 804 on a seven-segment calculator, flip it 180°, and the display reads:

hOB

Or, with leading zeros on the source string:

0804 → hOBO

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

Musical pitch

Heard as a frequency, 804 Hz is closest to:

Concert pitch (A4 = 440 Hz): G5 (784 Hz, +44¢)
Scientific pitch (C4 = 256 Hz): G♯5 (812.7 Hz, -19¢)
Baroque pitch (A4 = 415 Hz): G♯5 (783.4 Hz, +45¢ — about midway to A5)