Number

857

857 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Cousin Prime Deficient Number Evil Number Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Historical context — 857 AD

Calendar year

Year 857 (DCCCLVII) was a common year starting on Friday of the Julian calendar.

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Historical context — 857 BC

Decade

This article concerns the period 859 BC – 850 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: Monday
January 1, 857
Ended on: Monday
December 31, 857
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: 1,169
1169 years before 2026.

In other calendars

Hebrew: 4617 / 4618 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 242 / 243 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Fire zodiac:Ox
Sexagenary cycle position 14 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1400 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 235 / 236 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 849 / 850 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 779 / 778 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 20
Digit product: 280
Digital root: 2
Palindrome: No
Bit width: 10 bits
Reversed: 758
Recamán's sequence: a(817) = 857
Square (n²): 734,449
Cube (n³): 629,422,793
Divisor count: 2
σ(n) — sum of divisors: 858
φ(n) — Euler's totient: 856

Primality

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

Divisors & multiples

All divisors (2)

1 · 857

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 857)

1 × 857

First multiples

857 · 1,714 (double) · 2,571 · 3,428 · 4,285 · 5,142 · 5,999 · 6,856 · 7,713 · 8,570

Sums & aliquot sequence

As a sum of two squares: 4² + 29²

As consecutive integers: 428 + 429

Representations

In words: eight hundred fifty-seven
Ordinal: 857th
Roman numeral: DCCCLVII
Binary: 1101011001
Octal: 1531
Hexadecimal: 0x359
Base64: A1k=
One's complement: 64,678 (16-bit)

In other bases

ternary (3) 1011202

quaternary (4) 31121

quinary (5) 11412

senary (6) 3545

septenary (7) 2333

nonary (9) 1152

undecimal (11) 70a

duodecimal (12) 5b5

tridecimal (13) 50c

tetradecimal (14) 453

pentadecimal (15) 3c2

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ωνζʹ
Mayan (base 20): 𝋢·𝋢·𝋱
Chinese: 八百五十七
Chinese (financial): 捌佰伍拾柒

In other modern scripts

Eastern Arabic ٨٥٧ Devanagari ८५७ Bengali ৮৫৭ Tamil ௮௫௭ Thai ๘๕๗ Tibetan ༨༥༧ Khmer ៨៥៧ Lao ໘໕໗ Burmese ၈၅၇

Digit at this position in famous constants

π — Pi (π): Digit 857 = 0
e — Euler's number (e): Digit 857 = 3
φ — Golden ratio (φ): Digit 857 = 3
√2 — Pythagoras's (√2): Digit 857 = 6
ln 2 — Natural log of 2: Digit 857 = 8
γ — Euler-Mascheroni (γ): Digit 857 = 7

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 853 (gap of 4)
Next prime: 859 (gap of 2)

Pair status: twin with 859, cousin with 853.

Unicode codepoint

Combining Asterisk Below

U+0359

Non-spacing mark (Mn)

UTF-8 encoding: CD 99 (2 bytes).

Lookup U+0359 on Compart ↗ Lookup on FileFormat.Info ↗

Code page identifier

Code page 857 is DOS Turkish — DOS code page for Turkish.

Code pages are integer identifiers used by Windows and other systems to refer to specific character encodings.

Microsoft code page reference ↗

Hex color

#000359

RGB(0, 3, 89)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.89.

Address: 0.0.3.89
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.89

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

NANP area code 857

The number 857 is an active NANP area code (North American Numbering Plan).

Primary area: Boston
Region: Massachusetts
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 857 ↗