86
86 is a composite number, even, a calendar year.
86 (eighty-six) is an even 2-digit number. It is a composite number with 4 divisors, and factors as 2 × 43. Written other ways, in Roman numerals it is LXXXVI and in binary, 1010110.
Interestingness
Historical context — 86 AD
Calendar year
AD 86 (LXXXVI) was a common year starting on Sunday of the Julian calendar.
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Historical context — 86 BC
Calendar year
Year 86 BC was a year of the pre-Julian Roman calendar.
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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
-
Tuesday
January 1, 86
- Ended on
-
Tuesday
December 31, 86
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
80s
80–89
- Century
-
1st century
1–100
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,940
1940 years before 2026.
In other calendars
- Hebrew
-
3846 / 3847 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Fire zodiac:Dog
Sexagenary cycle position 23 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
629 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
78 / 79 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
8 / 7 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 × 43
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√86 = [9; (3, 1, 1, 1, 8, 1, 1, 1, 3, 18)]
Period length 10 — the block in parentheses repeats forever.
Representations
- In words
- eighty-six
- Ordinal
- 86th
- Roman numeral
- LXXXVI
- Binary
- 1010110
- Octal
- 126
- Hexadecimal
- 0x56
- Base64
- Vg==
- One's complement
- 169 (8-bit)
- Scientific notation
- 8.6 × 10¹
- As a duration
- 86 s = 1 minute, 26 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- πϛʹ
- Mayan (base 20)
- 𝋤·𝋦
- Chinese
- 八十六
- Chinese (financial)
- 捌拾陸
Digit at this position in famous constants
- π — Pi (π)
- Digit 86 = 0
- e — Euler's number (e)
- Digit 86 = 3
- φ — Golden ratio (φ)
- Digit 86 = 2
- √2 — Pythagoras's (√2)
- Digit 86 = 3
- ln 2 — Natural log of 2
- Digit 86 = 8
- γ — Euler-Mascheroni (γ)
- Digit 86 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 86, here are decompositions:
- 3 + 83 = 86
- 7 + 79 = 86
- 13 + 73 = 86
- 19 + 67 = 86
- 43 + 43 = 86
As an ASCII codepoint, 86 is V. Printable ASCII character V.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.86.
- Address
- 0.0.0.86
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.86
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Matches numbered highway designation:
- I-86 — Two segments: New York's Southern Tier and Idaho.
Heard as a frequency, 86 Hz is closest to:
- Concert pitch (A4 = 440 Hz): F2 (87.3 Hz, -26¢)
- Scientific pitch (C4 = 256 Hz): F2 (85.4 Hz, +12¢)
- Baroque pitch (A4 = 415 Hz): F♯2 (87.2 Hz, -25¢)
As a MIDI note number, 86 is D6 (1174.7 Hz at concert pitch).
On the periodic table, atomic number 86 is Radon (Rn) — period 6.
Related reading
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.