1,388
1,388 is a composite number, even, a calendar year.
1,388 (one thousand three hundred eighty-eight) is an even 4-digit number. It is a composite number with 6 divisors, and factors as 2² × 347. Written other ways, in Roman numerals it is MCCCLXXXVIII and in binary, 10101101100.
Interestingness
Historical context — 1388 AD
Calendar year
Year 1388 (MCCCLXXXVIII) was a leap year starting on Wednesday of the Julian calendar.
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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
-
Tuesday
January 1, 1388
- Ended on
-
Wednesday
December 31, 1388
- 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
-
638
638 years before 2026.
In other calendars
- Hebrew
-
5148 / 5149 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
789 / 790 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Earth zodiac:Dragon
Sexagenary cycle position 5 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
1931 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
766 / 767 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
1380 / 1381 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1310 / 1309 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 2 × 347
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√1,388 = [37; (3, 1, 9, 1, 8, 2, 2, 5, 3, 18, 3, 5, 2, 2, 8, 1, 9, 1, 3, 74)]
Period length 20 — the block in parentheses repeats forever.
Representations
- In words
- one thousand three hundred eighty-eight
- Ordinal
- 1388th
- Roman numeral
- MCCCLXXXVIII
- Binary
- 10101101100
- Octal
- 2554
- Hexadecimal
- 0x56C
- Base64
- BWw=
- One's complement
- 64,147 (16-bit)
- Scientific notation
- 1.388 × 10³
- As a duration
- 1,388 s = 23 minutes, 8 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵ατπηʹ
- Mayan (base 20)
- 𝋣·𝋩·𝋨
- Chinese
- 一千三百八十八
- Chinese (financial)
- 壹仟參佰捌拾捌
Digit at this position in famous constants
- π — Pi (π)
- Digit 1,388 = 2
- e — Euler's number (e)
- Digit 1,388 = 9
- φ — Golden ratio (φ)
- Digit 1,388 = 9
- √2 — Pythagoras's (√2)
- Digit 1,388 = 2
- ln 2 — Natural log of 2
- Digit 1,388 = 3
- γ — Euler-Mascheroni (γ)
- Digit 1,388 = 0
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1388, here are decompositions:
- 7 + 1381 = 1388
- 61 + 1327 = 1388
- 67 + 1321 = 1388
- 97 + 1291 = 1388
- 109 + 1279 = 1388
- 139 + 1249 = 1388
- 151 + 1237 = 1388
- 157 + 1231 = 1388
Showing the first eight; more decompositions exist.
UTF-8 encoding: D5 AC (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.5.108.
- Address
- 0.0.5.108
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.5.108
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 1,388 Hz is closest to:
- Concert pitch (A4 = 440 Hz): F6 (1396.9 Hz, -11¢)
- Scientific pitch (C4 = 256 Hz): F6 (1366.9 Hz, +27¢)
- Baroque pitch (A4 = 415 Hz): F♯6 (1395.9 Hz, -10¢)
The digit sequence 1388 first appears in π at position 3,761 of the decimal expansion (the 3,761ordinal-suffix:st 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.
Related reading
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.