667
667 is a composite number, odd, a calendar year.
667 (six hundred sixty-seven) is an odd 3-digit number. It is a composite number with 4 divisors, and factors as 23 × 29. Written other ways, in Roman numerals it is DCLXVII and in binary, 1010011011.
Interestingness
Historical context — 667 AD
Calendar year
Year 667 (DCLXVII) was a common year starting on Friday of the Julian calendar.
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Historical context — 667 BC
Calendar year
The year 667 BC was a year of the pre-Julian Roman 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
-
Tuesday
January 1, 667
- Ended on
-
Tuesday
December 31, 667
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
660s
660–669
- Century
-
7th century
601–700
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,359
1359 years before 2026.
In other calendars
- Hebrew
-
4427 / 4428 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
46 / 47 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Fire zodiac:Rabbit
Sexagenary cycle position 4 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
1210 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
45 / 46 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
659 / 660 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
589 / 588 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 23 × 29
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√667 = [25; (1, 4, 1, 3, 7, 8, 2, 8, 7, 3, 1, 4, 1, 50)]
Period length 14 — the block in parentheses repeats forever.
Representations
- In words
- six hundred sixty-seven
- Ordinal
- 667th
- Roman numeral
- DCLXVII
- Binary
- 1010011011
- Octal
- 1233
- Hexadecimal
- 0x29B
- Base64
- Aps=
- One's complement
- 64,868 (16-bit)
- Scientific notation
- 6.67 × 10²
- As a duration
- 667 s = 11 minutes, 7 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- χξζʹ
- Mayan (base 20)
- 𝋡·𝋭·𝋧
- Chinese
- 六百六十七
- Chinese (financial)
- 陸佰陸拾柒
Digit at this position in famous constants
- π — Pi (π)
- Digit 667 = 3
- e — Euler's number (e)
- Digit 667 = 9
- φ — Golden ratio (φ)
- Digit 667 = 3
- √2 — Pythagoras's (√2)
- Digit 667 = 6
- ln 2 — Natural log of 2
- Digit 667 = 3
- γ — Euler-Mascheroni (γ)
- Digit 667 = 2
Also seen as
UTF-8 encoding: CA 9B (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.2.155.
- Address
- 0.0.2.155
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.2.155
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 667 is an active NANP area code (North American Numbering Plan).
- Primary area
- Baltimore
- Region
- Maryland
- 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, 667 Hz is closest to:
- Concert pitch (A4 = 440 Hz): E5 (659.3 Hz, +20¢)
- Scientific pitch (C4 = 256 Hz): F5 (683.4 Hz, -42¢)
- Baroque pitch (A4 = 415 Hz): F5 (658.8 Hz, +21¢)
Related reading
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.