1,561
1,561 is a composite number, odd, a calendar year.
Notable events — 1561 AD
- Aug 19 Mary Queen of Scots returns to Scotland from France.
- Undated Madrid becomes Spain's capital under Philip II.
- Undated Francis Bacon is born in London.
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
-
Sunday
January 1, 1561
- Ended on
-
Sunday
December 31, 1561
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
1560s
1560–1569
- Century
-
16th century
1501–1600
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
465
465 years before 2026.
In other calendars
- Hebrew
-
5321 / 5322 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
968 / 969 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Metal zodiac:Rooster
Sexagenary cycle position 58 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2104 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
939 / 940 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1553 / 1554 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1483 / 1482 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 7 × 223
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand five hundred sixty-one
- Ordinal
- 1561st
- Roman numeral
- MDLXI
- Binary
- 11000011001
- Octal
- 3031
- Hexadecimal
- 0x619
- Base64
- Bhk=
- One's complement
- 63,974 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹 𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺
- Greek (Milesian)
- ͵αφξαʹ
- Mayan (base 20)
- 𝋣·𝋲·𝋡
- Chinese
- 一千五百六十一
- Chinese (financial)
- 壹仟伍佰陸拾壹
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,561 = 6
- e — Euler's number (e)
- Digit 1,561 = 1
- φ — Golden ratio (φ)
- Digit 1,561 = 6
- √2 — Pythagoras's (√2)
- Digit 1,561 = 7
- ln 2 — Natural log of 2
- Digit 1,561 = 6
- γ — Euler-Mascheroni (γ)
- Digit 1,561 = 3
Also seen as
UTF-8 encoding: D8 99 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.25.
- Address
- 0.0.6.25
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.6.25
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 1561 first appears in π at position 24,058 of the decimal expansion (the 24,058ordinal-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.