1,680
1,680 is a composite number, even, a calendar year.
1,680 (one thousand six hundred eighty) is an even 4-digit number. It is a composite number with 40 divisors, and factors as 2⁴ × 3 × 5 × 7. Its proper divisors sum to 4,272, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCLXXX and in binary, 11010010000.
Interestingness
Notable events — 1680 AD
- Aug 10 Pueblo Revolt drives Spanish colonists from New Mexico.
- Jul 8 A bright comet (Kirch's) is observed by telescope, the first such discovery.
- Dec 24 King Charles II prorogues Parliament again amid Exclusion strife.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
Year facts
- Year type
-
Leap year
Divisible by 4 and not by 100; February has 29 days.
- Days in year
- 366
- ISO weeks
- 52
- Started on
-
Monday
January 1, 1680
- Ended on
-
Tuesday
December 31, 1680
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Easter Sunday
-
April 21
Sunday, April 21, 1680
- Decade
-
1680s
1680–1689
- Century
-
17th century
1601–1700
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
346
346 years before 2026.
In other calendars
- Hebrew
-
5440 / 5441 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1090 / 1091 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Metal zodiac:Monkey
Sexagenary cycle position 57 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2223 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1058 / 1059 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1672 / 1673 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1602 / 1601 Saka
Indian national calendar; year starts in March.
Properties
- Parity
- Even
- Digit count
- 4
- Digit sum
- 15
- Digit product
- 0
- Digital root
- 6
- Palindrome
- No
- Bit width
- 11 bits
- Reversed
- 861
- Flips to (rotate 180°)
- 891
- Recamán's sequence
- a(828) = 1,680
- Square (n²)
- 2,822,400
- Cube (n³)
- 4,741,632,000
- Divisor count
- 40
- σ(n) — sum of divisors
- 5,952
- φ(n) — Euler's totient
- 384
- Sum of prime factors
- 23
Primality
Prime factorization: 2 4 × 3 × 5 × 7
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√1,680 = [40; (1, 80)]
Period length 2 — the block in parentheses repeats forever.
Representations
- In words
- one thousand six hundred eighty
- Ordinal
- 1680th
- Roman numeral
- MDCLXXX
- Binary
- 11010010000
- Octal
- 3220
- Hexadecimal
- 0x690
- Base64
- BpA=
- One's complement
- 63,855 (16-bit)
- Scientific notation
- 1.68 × 10³
- As a duration
- 1,680 s = 28 minutes
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 ·
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵αχπʹ
- Mayan (base 20)
- 𝋤·𝋤·𝋠
- Chinese
- 一千六百八十
- Chinese (financial)
- 壹仟陸佰捌拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,680 = 6
- e — Euler's number (e)
- Digit 1,680 = 9
- φ — Golden ratio (φ)
- Digit 1,680 = 8
- √2 — Pythagoras's (√2)
- Digit 1,680 = 1
- ln 2 — Natural log of 2
- Digit 1,680 = 1
- γ — Euler-Mascheroni (γ)
- Digit 1,680 = 7
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1680, here are decompositions:
- 11 + 1669 = 1680
- 13 + 1667 = 1680
- 17 + 1663 = 1680
- 23 + 1657 = 1680
- 43 + 1637 = 1680
- 53 + 1627 = 1680
- 59 + 1621 = 1680
- 61 + 1619 = 1680
Showing the first eight; more decompositions exist.
UTF-8 encoding: DA 90 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.144.
- Address
- 0.0.6.144
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.6.144
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 1,680 Hz is closest to:
- Concert pitch (A4 = 440 Hz): G♯6 (1661.2 Hz, +19¢)
- Scientific pitch (C4 = 256 Hz): A6 (1722.2 Hz, -43¢)
- Baroque pitch (A4 = 415 Hz): A6 (1660 Hz, +21¢)
The digit sequence 1680 first appears in π at position 13,798 of the decimal expansion (the 13,798ordinal-suffix:th 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°.