Number

868

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

868 (eight hundred sixty-eight) is an even 3-digit number. It is a composite number with 12 divisors, and factors as 2² × 7 × 31. Its proper divisors sum to 924, more than the number itself, making it an abundant number. Its digits read the same forwards and backwards, so it is a palindromic number. Written other ways, in Roman numerals it is DCCCLXVIII and in binary, 1101100100.

Abundant Number Cube-Free Flippable Odious Number Palindrome Pernicious Number Practical Number Recamán's Sequence Semiperfect Number Undulating Number Year

Interestingness

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7 notable facts · grade B

856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880

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Historical context — 868 AD

Calendar year

Year 868 (DCCCLXVIII) was a leap year starting on Thursday of the Julian calendar.

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

Historical context — 868 BC

Decade

This article concerns the period 869 BC – 860 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: 52
Started on: Sunday
January 1, 868
Ended on: Monday
December 31, 868
Friday the 13ths: 3
3 Friday the 13ths this year.
Decade: 860s
860–869
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,158
1158 years before 2026.

In other calendars

Hebrew: 4628 / 4629 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 253 / 255 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Earth zodiac:Rat
Sexagenary cycle position 25 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1411 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 246 / 247 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 860 / 861 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 790 / 789 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 22
Digit product: 384
Digital root: 4
Palindrome: Yes
Bit width: 10 bits
Flips to (rotate 180°): 898
Recamán's sequence: a(795) = 868
Square (n²): 753,424
Cube (n³): 653,972,032
Divisor count: 12
σ(n) — sum of divisors: 1,792
φ(n) — Euler's totient: 360
Sum of prime factors: 42

Primality

Prime factorization: 2 ² × 7 × 31

Nearest primes: 863 (−5) · 877 (+9)

Divisors & multiples

All divisors (12)

1 · 2 · 4 · 7 · 14 · 28 · 31 · 62 · 124 · 217 · 434 (half) · 868

Aliquot sum (sum of proper divisors): 924

Factor pairs (a × b = 868)

1 × 868

2 × 434

4 × 217

7 × 124

14 × 62

28 × 31

First multiples

868 · 1,736 (double) · 2,604 · 3,472 · 4,340 · 5,208 · 6,076 · 6,944 · 7,812 · 8,680

Sums & aliquot sequence

As consecutive integers: 121 + 122 + … + 127 105 + 106 + … + 112 13 + 14 + … + 43

Aliquot sequence: 868 → 924 → 1,764 → 3,423 → 1,825 → 469 → 75 → 49 → 8 → 7 → 1 → 0 — terminates at zero

Continued fraction of √n

√868 = [29; (2, 6, 19, 2, 19, 6, 2, 58)]

Period length 8 — the block in parentheses repeats forever.

Representations

In words: eight hundred sixty-eight
Ordinal: 868th
Roman numeral: DCCCLXVIII
Binary: 1101100100
Octal: 1544
Hexadecimal: 0x364
Base64: A2Q=
One's complement: 64,667 (16-bit)
Scientific notation: 8.68 × 10²
As a duration: 868 s = 14 minutes, 28 seconds

In other bases

ternary (3) 1012011

quaternary (4) 31210

quinary (5) 11433

senary (6) 4004

septenary (7) 2350

nonary (9) 1164

undecimal (11) 71a

duodecimal (12) 604

tridecimal (13) 51a

tetradecimal (14) 460

pentadecimal (15) 3cd

Palindromic in base 6

As an angle

868° = 2 × 360° + 148°

148° ≈ 2.583 rad

Compass bearing: SSE (south-southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ωξηʹ
Mayan (base 20): 𝋢·𝋣·𝋨
Chinese: 八百六十八
Chinese (financial): 捌佰陸拾捌

In other modern scripts

Eastern Arabic ٨٦٨ Devanagari ८६८ Bengali ৮৬৮ Tamil ௮௬௮ Thai ๘๖๘ Tibetan ༨༦༨ Khmer ៨៦៨ Lao ໘໖໘ Burmese ၈၆၈

Digit at this position in famous constants

π — Pi (π): Digit 868 = 2
e — Euler's number (e): Digit 868 = 8
φ — Golden ratio (φ): Digit 868 = 7
√2 — Pythagoras's (√2): Digit 868 = 2
ln 2 — Natural log of 2: Digit 868 = 3
γ — Euler-Mascheroni (γ): Digit 868 = 9

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 868, here are decompositions:

5 + 863 = 868
11 + 857 = 868
29 + 839 = 868
41 + 827 = 868
47 + 821 = 868
59 + 809 = 868
71 + 797 = 868
107 + 761 = 868

Showing the first eight; more decompositions exist.

Unicode codepoint

Combining Latin Small Letter E

U+0364

Non-spacing mark (Mn)

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

Lookup U+0364 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000364

RGB(0, 3, 100)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.100.

Address: 0.0.3.100
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.100

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

NANP area code 868

The number 868 is an active NANP area code (North American Numbering Plan).

Primary area: Statewide
Region: Trinidad and Tobago
Country: Trinidad and Tobago

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 868 ↗

Musical pitch

Heard as a frequency, 868 Hz is closest to:

Concert pitch (A4 = 440 Hz): A5 (880 Hz, -24¢)
Scientific pitch (C4 = 256 Hz): A5 (861.1 Hz, +14¢)
Baroque pitch (A4 = 415 Hz): A♯5 (879.4 Hz, -22¢)