Number

851

851 is a composite number, odd, a calendar year.

851 (eight hundred fifty-one) is an odd 3-digit number. It is a composite number with 4 divisors, and factors as 23 × 37. Written other ways, in Roman numerals it is DCCCLI and in binary, 1101010011.

Arithmetic Number Cube-Free Deficient Number Descending Digits Evil Number Recamán's Sequence Semiprime Squarefree Year

Interestingness

★ ★ ★ ★ ☆

6 notable facts · grade B

839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863

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Historical context — 851 AD

Calendar year

Year 851 (DCCCLI) was a common 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 — 851 BC

Decade

This article concerns the period 859 BC – 850 BC.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 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: Sunday
January 1, 851
Ended on: Sunday
December 31, 851
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 850s
850–859
Century: 9th century
801–900
Millennium: 1st millennium
1–1000
Years ago: 1,175
1175 years before 2026.

In other calendars

Hebrew: 4611 / 4612 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 236 / 237 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Metal zodiac:Goat
Sexagenary cycle position 8 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1394 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 229 / 230 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 843 / 844 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 773 / 772 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 14
Digit product: 40
Digital root: 5
Palindrome: No
Bit width: 10 bits
Reversed: 158
Recamán's sequence: a(829) = 851
Square (n²): 724,201
Cube (n³): 616,295,051
Divisor count: 4
σ(n) — sum of divisors: 912
φ(n) — Euler's totient: 792
Sum of prime factors: 60

Primality

Prime factorization: 23 × 37

Nearest primes: 839 (−12) · 853 (+2)

Divisors & multiples

All divisors (4)

1 · 23 · 37 · 851

Aliquot sum (sum of proper divisors): 61

Factor pairs (a × b = 851)

1 × 851

23 × 37

First multiples

851 · 1,702 (double) · 2,553 · 3,404 · 4,255 · 5,106 · 5,957 · 6,808 · 7,659 · 8,510

Sums & aliquot sequence

As consecutive integers: 425 + 426 26 + 27 + … + 48 5 + 6 + … + 41

Aliquot sequence: 851 → 61 → 1 → 0 — terminates at zero

Continued fraction of √n

√851 = [29; (5, 1, 4, 2, 7, 1, 7, 2, 4, 1, 5, 58)]

Period length 12 — the block in parentheses repeats forever.

Representations

In words: eight hundred fifty-one
Ordinal: 851st
Roman numeral: DCCCLI
Binary: 1101010011
Octal: 1523
Hexadecimal: 0x353
Base64: A1M=
One's complement: 64,684 (16-bit)
Scientific notation: 8.51 × 10²
As a duration: 851 s = 14 minutes, 11 seconds

In other bases

ternary (3) 1011112

quaternary (4) 31103

quinary (5) 11401

senary (6) 3535

septenary (7) 2324

nonary (9) 1145

undecimal (11) 704

duodecimal (12) 5ab

tridecimal (13) 506

tetradecimal (14) 44b

pentadecimal (15) 3bb

Palindromic in base 16

As an angle

851° = 2 × 360° + 131°

131° ≈ 2.286 rad

Compass bearing: SE (southeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): ωναʹ
Mayan (base 20): 𝋢·𝋢·𝋫
Chinese: 八百五十一
Chinese (financial): 捌佰伍拾壹

In other modern scripts

Eastern Arabic ٨٥١ Devanagari ८५१ Bengali ৮৫১ Tamil ௮௫௧ Thai ๘๕๑ Tibetan ༨༥༡ Khmer ៨៥១ Lao ໘໕໑ Burmese ၈၅၁

Digit at this position in famous constants

π — Pi (π): Digit 851 = 1
e — Euler's number (e): Digit 851 = 8
φ — Golden ratio (φ): Digit 851 = 3
√2 — Pythagoras's (√2): Digit 851 = 7
ln 2 — Natural log of 2: Digit 851 = 2
γ — Euler-Mascheroni (γ): Digit 851 = 5

Also seen as

Unicode codepoint

Combining X Below

U+0353

Non-spacing mark (Mn)

UTF-8 encoding: CD 93 (2 bytes).

Lookup U+0353 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000353

RGB(0, 3, 83)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.83.

Address: 0.0.3.83
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.83

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

Musical pitch

Heard as a frequency, 851 Hz is closest to:

Concert pitch (A4 = 440 Hz): G♯5 (830.6 Hz, +42¢)
Scientific pitch (C4 = 256 Hz): A5 (861.1 Hz, -20¢)
Baroque pitch (A4 = 415 Hz): A5 (830 Hz, +43¢)