1,643
1,643 is a composite number, odd, a calendar year.
Notable events — 1643 AD
- May 14 Louis XIV becomes king of France at age four; his mother Anne of Austria becomes regent.
- May 19 France defeats Spain at Rocroi, signaling the end of Spanish military dominance.
- Sep 25 Parliament adopts the Solemn League and Covenant with Scotland.
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
-
53
Long year: contains 53 ISO weeks.
- Started on
-
Thursday
January 1, 1643
- Ended on
-
Thursday
December 31, 1643
- Friday the 13ths
-
3
3 Friday the 13ths this year.
- Easter Sunday
-
April 5
Sunday, April 5, 1643
- Decade
-
1640s
1640–1649
- Century
-
17th century
1601–1700
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
383
383 years before 2026.
In other calendars
- Hebrew
-
5403 / 5404 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1052 / 1053 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Water zodiac:Goat
Sexagenary cycle position 20 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2186 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1021 / 1022 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1635 / 1636 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1565 / 1564 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 31 × 53
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand six hundred forty-three
- Ordinal
- 1643rd
- Roman numeral
- MDCXLIII
- Binary
- 11001101011
- Octal
- 3153
- Hexadecimal
- 0x66B
- Base64
- Bms=
- One's complement
- 63,892 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺
- Greek (Milesian)
- ͵αχμγʹ
- Mayan (base 20)
- 𝋤·𝋢·𝋣
- Chinese
- 一千六百四十三
- Chinese (financial)
- 壹仟陸佰肆拾參
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,643 = 9
- e — Euler's number (e)
- Digit 1,643 = 8
- φ — Golden ratio (φ)
- Digit 1,643 = 0
- √2 — Pythagoras's (√2)
- Digit 1,643 = 3
- ln 2 — Natural log of 2
- Digit 1,643 = 8
- γ — Euler-Mascheroni (γ)
- Digit 1,643 = 2
Also seen as
UTF-8 encoding: D9 AB (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.107.
- Address
- 0.0.6.107
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.6.107
Unspecified address (0.0.0.0/8) — "this network" placeholder.
This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.
Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.
The digit sequence 1643 first appears in π at position 5,754 of the decimal expansion (the 5,754ordinal-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.