Number

1,380

1,380 is a composite number, even, a calendar year.

1,380 (one thousand three hundred eighty) is an even 4-digit number. It is a composite number with 24 divisors, and factors as 2² × 3 × 5 × 23. Its proper divisors sum to 2,652, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MCCCLXXX and in binary, 10101100100.

Abundant Number Arithmetic Number Cube-Free Gapful Number Harshad / Niven Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number Year

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

1,368 1,369 1,370 1,371 1,372 1,373 1,374 1,375 1,376 1,377 1,378 1,379 1,380 1,381 1,382 1,383 1,384 1,385 1,386 1,387 1,388 1,389 1,390 1,391 1,392

less more

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 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

Parity: Even
Digit count: 4
Digit sum: 12
Digit product: 0
Digital root: 3
Palindrome: No
Bit width: 11 bits
Reversed: 831
Recamán's sequence: a(8,368) = 1,380
Square (n²): 1,904,400
Cube (n³): 2,628,072,000
Divisor count: 24
σ(n) — sum of divisors: 4,032
φ(n) — Euler's totient: 352
Sum of prime factors: 35

Primality

Prime factorization: 2 ² × 3 × 5 × 23

Nearest primes: 1,373 (−7) · 1,381 (+1)

Divisors & multiples

All divisors (24)

1 · 2 · 3 · 4 · 5 · 6 · 10 · 12 · 15 · 20 · 23 · 30 · 46 · 60 · 69 · 92 · 115 · 138 · 230 · 276 · 345 · 460 · 690 (half) · 1380

Aliquot sum (sum of proper divisors): 2,652

Factor pairs (a × b = 1,380)

1 × 1380

2 × 690

3 × 460

4 × 345

5 × 276

6 × 230

10 × 138

12 × 115

15 × 92

20 × 69

23 × 60

30 × 46

First multiples

1,380 · 2,760 (double) · 4,140 · 5,520 · 6,900 · 8,280 · 9,660 · 11,040 · 12,420 · 13,800

Sums & aliquot sequence

As consecutive integers: 459 + 460 + 461 274 + 275 + 276 + 277 + 278 169 + 170 + … + 176 85 + 86 + … + 99

Aliquot sequence: 1,380 → 2,652 → 4,404 → 5,900 → 7,120 → 9,620 → 12,724 → 9,550 → 8,306 → 4,156 → 3,124 → 2,924 → 2,620 → 2,924 — enters a cycle

Continued fraction of √n

√1,380 = [37; (6, 1, 2, 1, 6, 74)]

Period length 6 — the block in parentheses repeats forever.

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)
Scientific notation: 1.38 × 10³
As a duration: 1,380 s = 23 minutes

In other bases

ternary (3) 1220010

quaternary (4) 111210

quinary (5) 21010

senary (6) 10220

septenary (7) 4011

nonary (9) 1803

undecimal (11) 1045

duodecimal (12) 970

tridecimal (13) 822

tetradecimal (14) 708

pentadecimal (15) 620

As an angle

1,380° = 3 × 360° + 300°

300° ≈ 5.236 rad

Compass bearing: WNW (west-northwest)

Why does a circle have 360 degrees? →

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

In other modern scripts

Eastern Arabic ١٣٨٠ Devanagari १३८० Bengali ১৩৮০ Tamil ௧௩௮௦ Thai ๑๓๘๐ Tibetan ༡༣༨༠ Khmer ១៣៨០ Lao ໑໓໘໐ Burmese ၁၃၈၀

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 decomposition

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.

Unicode codepoint

Armenian Small Letter Da

U+0564

Lowercase letter (Ll)

UTF-8 encoding: D5 A4 (2 bytes).

Lookup U+0564 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000564

RGB(0, 5, 100)

IPv4 address

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.

Musical pitch

Heard as a frequency, 1,380 Hz is closest to:

Concert pitch (A4 = 440 Hz): F6 (1396.9 Hz, -21¢)
Scientific pitch (C4 = 256 Hz): F6 (1366.9 Hz, +17¢)
Baroque pitch (A4 = 415 Hz): F♯6 (1395.9 Hz, -20¢)

Position in π

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.

Look up 1380 on Pi Search ↗