1,986
1,986 is a composite number, even, a calendar year.
1,986 (one thousand nine hundred eighty-six) is an even 4-digit number. It is a composite number with 8 divisors, and factors as 2 × 3 × 331. Its proper divisors sum to 1,998, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MCMLXXXVI and in binary, 11111000010.
Interestingness
Notable events — 1986 AD
- Jan 28 The Space Shuttle Challenger explodes 73 seconds after launch; all seven aboard die.
- Feb 19 The Soviet Union launches the Mir space station.
- Feb 25 The People Power Revolution ousts Philippine President Ferdinand Marcos.
- Feb 28 Swedish Prime Minister Olof Palme is assassinated on a Stockholm street.
- Apr 26 Reactor 4 at the Chernobyl nuclear plant explodes, contaminating much of Europe.
- Nov 25 The Iran-Contra affair is publicly revealed in the US.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
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
-
Wednesday
January 1, 1986
- Ended on
-
Wednesday
December 31, 1986
- Friday the 13ths
-
1
One Friday the 13th this year.
- Easter Sunday
-
March 30
Sunday, March 30, 1986
- Decade
-
1980s
1980–1989
- Century
-
20th century
1901–2000
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
40
40 years before 2026.
- FIFA World Cup
-
Yes
Men's FIFA World Cup is held every four years (skipped 1942 and 1946 due to WWII).
In other calendars
- Hebrew
-
5746 / 5747 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1406 / 1407 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Fire zodiac:Tiger
Sexagenary cycle position 3 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2529 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1364 / 1365 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1978 / 1979 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1908 / 1907 Saka
Indian national calendar; year starts in March.
- Japanese
-
Shōwa 61
Reign-era counting from the start of each emperor's reign.
Properties
- Parity
- Even
- Digit count
- 4
- Digit sum
- 24
- Digit product
- 432
- Digital root
- 6
- Palindrome
- No
- Bit width
- 11 bits
- Reversed
- 6,891
- Flips to (rotate 180°)
- 9,861
- Recamán's sequence
- a(3,779) = 1,986
- Square (n²)
- 3,944,196
- Cube (n³)
- 7,833,173,256
- Divisor count
- 8
- σ(n) — sum of divisors
- 3,984
- φ(n) — Euler's totient
- 660
- Sum of prime factors
- 336
Primality
Prime factorization: 2 × 3 × 331
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√1,986 = [44; (1, 1, 3, 2, 1, 2, 5, 1, 1, 3, 44, 3, 1, 1, 5, 2, 1, 2, 3, 1, 1, 88)]
Period length 22 — the block in parentheses repeats forever.
Representations
- In words
- one thousand nine hundred eighty-six
- Ordinal
- 1986th
- Roman numeral
- MCMLXXXVI
- Binary
- 11111000010
- Octal
- 3702
- Hexadecimal
- 0x7C2
- Base64
- B8I=
- One's complement
- 63,549 (16-bit)
- Scientific notation
- 1.986 × 10³
- As a duration
- 1,986 s = 33 minutes, 6 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵αϡπϛʹ
- Mayan (base 20)
- 𝋤·𝋳·𝋦
- Chinese
- 一千九百八十六
- Chinese (financial)
- 壹仟玖佰捌拾陸
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,986 = 1
- e — Euler's number (e)
- Digit 1,986 = 7
- φ — Golden ratio (φ)
- Digit 1,986 = 0
- √2 — Pythagoras's (√2)
- Digit 1,986 = 7
- ln 2 — Natural log of 2
- Digit 1,986 = 6
- γ — Euler-Mascheroni (γ)
- Digit 1,986 = 8
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1986, here are decompositions:
- 7 + 1979 = 1986
- 13 + 1973 = 1986
- 37 + 1949 = 1986
- 53 + 1933 = 1986
- 73 + 1913 = 1986
- 79 + 1907 = 1986
- 97 + 1889 = 1986
- 107 + 1879 = 1986
Showing the first eight; more decompositions exist.
UTF-8 encoding: DF 82 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.194.
- Address
- 0.0.7.194
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.7.194
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 1,986 Hz is closest to:
- Concert pitch (A4 = 440 Hz): B6 (1975.5 Hz, +9¢)
- Scientific pitch (C4 = 256 Hz): B6 (1933.1 Hz, +47¢ — about midway to C7)
- Baroque pitch (A4 = 415 Hz): C7 (1974.1 Hz, +10¢)
The digit sequence 1986 first appears in π at position 4,531 of the decimal expansion (the 4,531ordinal-suffix:st digit after the integer 3).
Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.
Related reading
- Babylonian numerals — The base-60 cuneiform system that gave us 60 minutes, 60 seconds, and 360°.