320
320 is a composite number, even, a calendar year.
320 (three hundred twenty) is an even 3-digit number. It is a composite number with 14 divisors, and factors as 2⁶ × 5. Its proper divisors sum to 442, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is CCCXX and in binary, 101000000.
Interestingness
Historical context — 320 AD
Calendar year
Year 320 (CCCXX) was a leap year starting on Friday of the Julian calendar.
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Historical context — 320 BC
Calendar year
Year 320 BC was a year of the pre-Julian Roman 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
-
53
Long year: contains 53 ISO weeks.
- Started on
-
Thursday
January 1, 320
- Ended on
-
Friday
December 31, 320
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
320s
320–329
- Century
-
4th century
301–400
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,706
1706 years before 2026.
In other calendars
- Hebrew
-
4080 / 4081 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Metal zodiac:Dragon
Sexagenary cycle position 17 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
863 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
312 / 313 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
242 / 241 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 6 × 5
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√320 = [17; (1, 7, 1, 34)]
Period length 4 — the block in parentheses repeats forever.
Representations
- In words
- three hundred twenty
- Ordinal
- 320th
- Roman numeral
- CCCXX
- Binary
- 101000000
- Octal
- 500
- Hexadecimal
- 0x140
- Base64
- AUA=
- One's complement
- 65,215 (16-bit)
- Scientific notation
- 3.2 × 10²
- As a duration
- 320 s = 5 minutes, 20 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹𒁹𒁹 𒌋𒌋
- Egyptian hieroglyphic
- 𓍢𓍢𓍢𓎆𓎆
- Greek (Milesian)
- τκʹ
- Mayan (base 20)
- 𝋰·𝋠
- Chinese
- 三百二十
- Chinese (financial)
- 參佰貳拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 320 = 1
- e — Euler's number (e)
- Digit 320 = 3
- φ — Golden ratio (φ)
- Digit 320 = 3
- √2 — Pythagoras's (√2)
- Digit 320 = 8
- ln 2 — Natural log of 2
- Digit 320 = 6
- γ — Euler-Mascheroni (γ)
- Digit 320 = 2
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 320, here are decompositions:
- 3 + 317 = 320
- 7 + 313 = 320
- 13 + 307 = 320
- 37 + 283 = 320
- 43 + 277 = 320
- 79 + 241 = 320
- 97 + 223 = 320
- 109 + 211 = 320
Showing the first eight; more decompositions exist.
UTF-8 encoding: C5 80 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.64.
- Address
- 0.0.1.64
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.1.64
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 320 is an active NANP area code (North American Numbering Plan).
- Primary area
- St. Cloud
- Region
- Minnesota
- Country
- United States
Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.
Heard as a frequency, 320 Hz is closest to:
- Concert pitch (A4 = 440 Hz): D♯4 (311.1 Hz, +49¢ — about midway to E4)
- Scientific pitch (C4 = 256 Hz): E4 (322.5 Hz, -14¢)
- Baroque pitch (A4 = 415 Hz): E4 (310.9 Hz, +50¢ — about midway to F4)
Related reading
- Mayan numerals — Vigesimal dots-and-bars with a shell zero — one of the earliest true zeros.