1,669
1,669 is a prime, odd, a calendar year.
1,669 (one thousand six hundred sixty-nine) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is MDCLXIX and in binary, 11010000101.
Interestingness
Notable events — 1669 AD
- Sep 6 The Ottomans capture Candia (Heraklion), ending the long siege of Crete.
- Aug 30 Rembrandt is buried in Amsterdam.
- Dec 28 Hennig Brand discovers phosphorus.
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
-
Tuesday
January 1, 1669
- Ended on
-
Tuesday
December 31, 1669
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Easter Sunday
-
April 21
Sunday, April 21, 1669
- Decade
-
1660s
1660–1669
- Century
-
17th century
1601–1700
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
357
357 years before 2026.
In other calendars
- Hebrew
-
5429 / 5430 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1079 / 1080 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Earth zodiac:Rooster
Sexagenary cycle position 46 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2212 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1047 / 1048 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1661 / 1662 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1591 / 1590 Saka
Indian national calendar; year starts in March.
Properties
Primality
1,669 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√1,669 = [40; (1, 5, 1, 4, 1, 1, 2, 3, 1, 2, 3, 1, 15, 1, 1, 3, 26, 1, 19, 2, 6, 3, 8, 1, …)]
Period length 53 — the block in parentheses repeats forever.
Representations
- In words
- one thousand six hundred sixty-nine
- Ordinal
- 1669th
- Roman numeral
- MDCLXIX
- Binary
- 11010000101
- Octal
- 3205
- Hexadecimal
- 0x685
- Base64
- BoU=
- One's complement
- 63,866 (16-bit)
- Scientific notation
- 1.669 × 10³
- As a duration
- 1,669 s = 27 minutes, 49 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵αχξθʹ
- Mayan (base 20)
- 𝋤·𝋣·𝋩
- Chinese
- 一千六百六十九
- Chinese (financial)
- 壹仟陸佰陸拾玖
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,669 = 3
- e — Euler's number (e)
- Digit 1,669 = 2
- φ — Golden ratio (φ)
- Digit 1,669 = 6
- √2 — Pythagoras's (√2)
- Digit 1,669 = 9
- ln 2 — Natural log of 2
- Digit 1,669 = 6
- γ — Euler-Mascheroni (γ)
- Digit 1,669 = 0
Also seen as
UTF-8 encoding: DA 85 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.133.
- Address
- 0.0.6.133
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.6.133
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 1,669 Hz is closest to:
- Concert pitch (A4 = 440 Hz): G♯6 (1661.2 Hz, +8¢)
- Scientific pitch (C4 = 256 Hz): G♯6 (1625.5 Hz, +46¢ — about midway to A6)
- Baroque pitch (A4 = 415 Hz): A6 (1660 Hz, +9¢)
The digit sequence 1669 first appears in π at position 4,653 of the decimal expansion (the 4,653ordinal-suffix:rd 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
- Prime numbers — The building blocks of arithmetic: what primes are, why they matter, and how we find them.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.