2,009
2,009 is a composite number, odd, a calendar year.
Notable events — 2009 AD
- Jan 3 The genesis block of the Bitcoin blockchain is mined.
- Jan 15 Captain Sully lands US Airways 1549 on the Hudson River; all 155 aboard survive.
- Jan 20 Barack Obama is inaugurated as the 44th US President.
- Apr 24 The H1N1 swine flu emerges, leading to a global pandemic declared in June.
- Jun 25 Michael Jackson dies of cardiac arrest at age 50.
Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0
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
-
53
Long year: contains 53 ISO weeks.
- Started on
-
Thursday
January 1, 2009
- Ended on
-
Thursday
December 31, 2009
- Friday the 13ths
-
3
3 Friday the 13ths this year.
- Easter Sunday
-
April 12
Sunday, April 12, 2009
- Decade
-
2000s
2000–2009
- Century
-
21st century
2001–2100
- Millennium
-
3rd millennium
2001–3000
- Years ago
-
17
17 years before 2026.
In other calendars
- Hebrew
-
5769 / 5770 AM
Rosh Hashanah falls in September/October.
- Islamic Hijri
-
1430 / 1431 AH
Lunar calendar; year spans differ from Gregorian.
- Chinese
-
Year of the zodiac:Earth zodiac:Ox
Sexagenary cycle position 26 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
2552 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Persian Solar Hijri
-
1387 / 1388 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
- Ethiopian
-
2001 / 2002 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
1931 / 1930 Saka
Indian national calendar; year starts in March.
- Japanese
-
Heisei 21
Reign-era counting from the start of each emperor's reign.
Properties
- Parity
- Odd
- Digit count
- 4
- Digit sum
- 11
- Digit product
- 0
- Digital root
- 2
- Palindrome
- No
- Bit width
- 11 bits
- Reversed
- 9,002
- Recamán's sequence
- a(3,733) = 2,009
- Square (n²)
- 4,036,081
- Cube (n³)
- 8,108,486,729
- Divisor count
- 6
- σ(n) — sum of divisors
- 2,394
- φ(n) — Euler's totient
- 1,680
- Sum of prime factors
- 55
Primality
Prime factorization: 7 2 × 41
Divisors & multiples
Sums & aliquot sequence
Representations
- In words
- two thousand nine
- Ordinal
- 2009th
- Roman numeral
- MMIX
- Binary
- 11111011001
- Octal
- 3731
- Hexadecimal
- 0x7D9
- Base64
- B9k=
- One's complement
- 63,526 (16-bit)
Historical numeral systems
- Babylonian (base 60)
- 𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓆼𓆼𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ͵βθʹ
- Mayan (base 20)
- 𝋥·𝋠·𝋩
- Chinese
- 二千零九
- Chinese (financial)
- 貳仟零玖
Digit at this position in famous constants
- π — Pi (π)
- Digit 2,009 = 0
- e — Euler's number (e)
- Digit 2,009 = 7
- φ — Golden ratio (φ)
- Digit 2,009 = 8
- √2 — Pythagoras's (√2)
- Digit 2,009 = 4
- ln 2 — Natural log of 2
- Digit 2,009 = 4
- γ — Euler-Mascheroni (γ)
- Digit 2,009 = 6
Also seen as
UTF-8 encoding: DF 99 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.217.
- Address
- 0.0.7.217
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.7.217
Unspecified address (0.0.0.0/8) — "this network" placeholder.
The digit sequence 2009 first appears in π at position 8,184 of the decimal expansion (the 8,184ordinal-suffix:th 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.