1,380
1,380 is a composite number, even, a calendar year.
Historical context — 1380 AD
Calendar year
Year 1380 (MCCCLXXX) was a leap year starting on Sunday of the Julian calendar.
Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback Read the full article on Wikipedia →
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
-
Saturday
January 1, 1380
- Ended on
-
Sunday
December 31, 1380
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
1380s
1380–1389
- Century
-
14th century
1301–1400
- Millennium
-
2nd millennium
1001–2000
- Years ago
-
646
646 years before 2026.
In other calendars
- Hebrew
-
5140 / 5141 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
781 / 782 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
-
1923 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
758 / 759 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1372 / 1373 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1302 / 1301 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 2 × 3 × 5 × 23
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- one thousand three hundred eighty
- Ordinal
- 1380th
- Roman numeral
- MCCCLXXX
- Binary
- 10101100100
- Octal
- 2544
- Hexadecimal
- 0x564
- Base64
- BWQ=
- One's complement
- 64,155 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹 ·
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
- Greek (Milesian)
- ͵ατπʹ
- Mayan (base 20)
- 𝋣·𝋩·𝋠
- Chinese
- 一千三百八十
- Chinese (financial)
- 壹仟參佰捌拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,380 = 6
- e — Euler's number (e)
- Digit 1,380 = 6
- φ — Golden ratio (φ)
- Digit 1,380 = 4
- √2 — Pythagoras's (√2)
- Digit 1,380 = 6
- ln 2 — Natural log of 2
- Digit 1,380 = 2
- γ — Euler-Mascheroni (γ)
- Digit 1,380 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1380, here are decompositions:
- 7 + 1373 = 1380
- 13 + 1367 = 1380
- 19 + 1361 = 1380
- 53 + 1327 = 1380
- 59 + 1321 = 1380
- 61 + 1319 = 1380
- 73 + 1307 = 1380
- 79 + 1301 = 1380
Showing the first eight; more decompositions exist.
UTF-8 encoding: D5 A4 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.5.100.
- Address
- 0.0.5.100
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.5.100
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 1380 first appears in π at position 11,977 of the decimal expansion (the 11,977ordinal-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.