38
38 is a composite number, even, a calendar year.
Historical context — 38 AD
Calendar year
AD 38 (XXXVIII) was a common year starting on Wednesday of the Julian calendar.
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Historical context — 38 BC
Calendar year
Year 38 BC was either a common year starting on Sunday or Monday or a leap year starting on Saturday, Sunday or Monday of the Julian calendar and a common year starting on Sunday of the Proleptic Julian calendar.
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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
-
Friday
January 1, 38
- Ended on
-
Friday
December 31, 38
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
30s
30–39
- Century
-
1st century
1–100
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,988
1988 years before 2026.
In other calendars
- Hebrew
-
3798 / 3799 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Earth zodiac:Dog
Sexagenary cycle position 35 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
581 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
30 / 31 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
-40 / -41 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 × 19
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√38 = [6; (6, 12)]
Period length 2 — the block in parentheses repeats forever.
Representations
- In words
- thirty-eight
- Ordinal
- 38th
- Roman numeral
- XXXVIII
- Binary
- 100110
- Octal
- 46
- Hexadecimal
- 0x26
- Base64
- Jg==
- One's complement
- 217 (8-bit)
- Scientific notation
- 3.8 × 10¹
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ληʹ
- Mayan (base 20)
- 𝋡·𝋲
- Chinese
- 三十八
- Chinese (financial)
- 參拾捌
Digit at this position in famous constants
- π — Pi (π)
- Digit 38 = 1
- e — Euler's number (e)
- Digit 38 = 7
- φ — Golden ratio (φ)
- Digit 38 = 7
- √2 — Pythagoras's (√2)
- Digit 38 = 5
- ln 2 — Natural log of 2
- Digit 38 = 0
- γ — Euler-Mascheroni (γ)
- Digit 38 = 0
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 38, here are decompositions:
- 7 + 31 = 38
- 19 + 19 = 38
As an ASCII codepoint, 38 is &. Printable ASCII character &.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.38.
- Address
- 0.0.0.38
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.38
Unspecified address (0.0.0.0/8) — "this network" placeholder.
As a geographic coordinate in degrees, this matches:
- 38th parallel (latitude) — The post-WWII division of Korea; also passes through Washington, D.C. (approximately).
Type 38 on a seven-segment calculator, flip it 180°, and the display reads:
BE
A staple of calculator humor since pocket calculators put digits in front of bored students.
Heard as a frequency, 38 Hz is closest to:
- Concert pitch (A4 = 440 Hz): D♯1 (-40¢)
- Scientific pitch (C4 = 256 Hz): D♯1 (-2¢)
On the periodic table, atomic number 38 is Strontium (Sr) — period 5.