220
220 is a composite number, even, a calendar year.
220 (two hundred twenty) is an even 3-digit number. It is a composite number with 12 divisors, and factors as 2² × 5 × 11. Its proper divisors sum to 284, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is CCXX and in binary, 11011100.
Interestingness
Historical context — 220 AD
Calendar year
Year 220 (CCXX) was a leap year starting on Saturday of the Julian calendar.
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Historical context — 220 BC
Calendar year
Year 220 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
- 52
- Started on
-
Saturday
January 1, 220
- Ended on
-
Sunday
December 31, 220
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
220s
220–229
- Century
-
3rd century
201–300
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,806
1806 years before 2026.
In other calendars
- Hebrew
-
3980 / 3981 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Metal zodiac:Rat
Sexagenary cycle position 37 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
763 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
212 / 213 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
142 / 141 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 2 × 5 × 11
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√220 = [14; (1, 4, 1, 28)]
Period length 4 — the block in parentheses repeats forever.
Representations
- In words
- two hundred twenty
- Ordinal
- 220th
- Roman numeral
- CCXX
- Binary
- 11011100
- Octal
- 334
- Hexadecimal
- 0xDC
- Base64
- 3A==
- One's complement
- 35 (8-bit)
- Scientific notation
- 2.2 × 10²
- As a duration
- 220 s = 3 minutes, 40 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹 𒌋𒌋𒌋𒌋
- Egyptian hieroglyphic
- 𓍢𓍢𓎆𓎆
- Greek (Milesian)
- σκʹ
- Mayan (base 20)
- 𝋫·𝋠
- Chinese
- 二百二十
- Chinese (financial)
- 貳佰貳拾
Digit at this position in famous constants
- π — Pi (π)
- Digit 220 = 6
- e — Euler's number (e)
- Digit 220 = 4
- φ — Golden ratio (φ)
- Digit 220 = 1
- √2 — Pythagoras's (√2)
- Digit 220 = 4
- ln 2 — Natural log of 2
- Digit 220 = 0
- γ — Euler-Mascheroni (γ)
- Digit 220 = 0
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 220, here are decompositions:
- 23 + 197 = 220
- 29 + 191 = 220
- 41 + 179 = 220
- 47 + 173 = 220
- 53 + 167 = 220
- 71 + 149 = 220
- 83 + 137 = 220
- 89 + 131 = 220
Showing the first eight; more decompositions exist.
UTF-8 encoding: C3 9C (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.220.
- Address
- 0.0.0.220
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.220
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The number 220 is an active NANP area code (North American Numbering Plan).
- Primary area
- Newark / Lancaster
- Region
- Ohio
- 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, 220 Hz is closest to:
- Concert pitch (A4 = 440 Hz): A3 (220 Hz, exact)
- Scientific pitch (C4 = 256 Hz): A3 (215.3 Hz, +38¢)
- Baroque pitch (A4 = 415 Hz): A♯3 (219.8 Hz, +1¢)
On an ingredients label, E220 is Sulphur dioxide, a preservative — a preservative in dried fruit and wine.
Related reading
- Amicable numbers — Pairs of numbers, each the sum of the other's divisors — a Pythagorean symbol of friendship.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.