857
857 is a prime, odd, a calendar year.
857 (eight hundred fifty-seven) is an odd 3-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is DCCCLVII and in binary, 1101011001.
Interestingness
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
Primality
857 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√857 = [29; (3, 1, 1, 1, 3, 1, 6, 1, 1, 6, 1, 3, 1, 1, 1, 3, 58)]
Period length 17 — the block in parentheses repeats forever.
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)
- Scientific notation
- 8.57 × 10²
- As a duration
- 857 s = 14 minutes, 17 seconds
As an angle
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
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
UTF-8 encoding: CD 99 (2 bytes).
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.
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.
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.
Heard as a frequency, 857 Hz is closest to:
- Concert pitch (A4 = 440 Hz): A5 (880 Hz, -46¢ — about midway to G♯5)
- Scientific pitch (C4 = 256 Hz): A5 (861.1 Hz, -8¢)
- Baroque pitch (A4 = 415 Hz): A♯5 (879.4 Hz, -45¢ — about midway to A5)
Related reading
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.