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Number

1,669

1,669 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Deficient Number Emirp Flippable Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Notable events — 1669 AD

  1. Sep 6 The Ottomans capture Candia (Heraklion), ending the long siege of Crete.
  2. Aug 30 Rembrandt is buried in Amsterdam.
  3. 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

Parity
Odd
Digit count
4
Digit sum
22
Digit product
324
Digital root
4
Palindrome
No
Bit width
11 bits
Reversed
9,661
Flips to (rotate 180°)
6,991
Recamán's sequence
a(806) = 1,669
Square (n²)
2,785,561
Cube (n³)
4,649,101,309
Divisor count
2
σ(n) — sum of divisors
1,670
φ(n) — Euler's totient
1,668

Primality

1,669 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 1669
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 1,669)
1 × 1669
First multiples
1,669 · 3,338 (double) · 5,007 · 6,676 · 8,345 · 10,014 · 11,683 · 13,352 · 15,021 · 16,690

Sums & aliquot sequence

As a sum of two squares: 15² + 38²
As consecutive integers: 834 + 835

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)
In other bases
ternary (3) 2021211
quaternary (4) 122011
quinary (5) 23134
senary (6) 11421
septenary (7) 4603
nonary (9) 2254
undecimal (11) 1288
duodecimal (12) b71
tridecimal (13) 9b5
tetradecimal (14) 873
pentadecimal (15) 764

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
In other modern scripts
Eastern Arabic ١٦٦٩ Devanagari १६६९ Bengali ১৬৬৯ Tamil ௧௬௬௯ Thai ๑๖๖๙ Tibetan ༡༦༦༩ Khmer ១៦៦៩ Lao ໑໖໖໙ Burmese ၁၆၆၉

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

Prime neighborhood

Adjacent primes:

  • Previous prime: 1,667 (gap of 2)
  • Next prime: 1,693 (gap of 24)

Pair status: twin with 1667.

Unicode codepoint
څ
Arabic Letter Hah With Three Dots Above
U+0685
Other letter (Lo)

UTF-8 encoding: DA 85 (2 bytes).

Hex color
#000685
RGB(0, 6, 133)
IPv4 address

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.

Possible US bank routing number

This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.

Routing number
000001669
Federal Reserve
United States Government

Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.

Position in π

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.