Number

909

909 is a composite number, odd, a calendar year.

Arithmetic Number Deficient Number Evil Number Flippable Palindrome Recamán's Sequence Year

Historical context — 909 AD

Calendar year

Year 909 (CMIX) was a common year starting on Sunday of the Julian calendar.

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Historical context — 909 BC

Decade

The 900s BC is a decade that lasted from 909 BC to 900 BC.

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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, 909
Ended on: Tuesday
December 31, 909
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 900s
900–909
Century: 10th century
901–1000
Millennium: 1st millennium
1–1000
Years ago: 1,117
1117 years before 2026.

In other calendars

Hebrew: 4669 / 4670 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 296 / 297 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Earth zodiac:Snake
Sexagenary cycle position 6 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1452 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 287 / 288 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 901 / 902 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 831 / 830 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 18
Digit product: 0
Digital root: 9
Palindrome: Yes
Bit width: 10 bits
Flips to (rotate 180°): 606
Recamán's sequence: a(449) = 909
Square (n²): 826,281
Cube (n³): 751,089,429
Divisor count: 6
σ(n) — sum of divisors: 1,326
φ(n) — Euler's totient: 600
Sum of prime factors: 107

Primality

Prime factorization: 3 ² × 101

Nearest primes: 907 (−2) · 911 (+2)

Divisors & multiples

All divisors (6)

1 · 3 · 9 · 101 · 303 · 909

Aliquot sum (sum of proper divisors): 417

Factor pairs (a × b = 909)

1 × 909

3 × 303

9 × 101

First multiples

909 · 1,818 (double) · 2,727 · 3,636 · 4,545 · 5,454 · 6,363 · 7,272 · 8,181 · 9,090

Sums & aliquot sequence

As a sum of two squares: 3² + 30²

As consecutive integers: 454 + 455 302 + 303 + 304 149 + 150 + 151 + 152 + 153 + 154 97 + 98 + … + 105

Aliquot sequence: 909 → 417 → 143 → 25 → 6 → 6 — reaches a perfect number

Representations

In words: nine hundred nine
Ordinal: 909th
Roman numeral: CMIX
Binary: 1110001101
Octal: 1615
Hexadecimal: 0x38D
Base64: A40=
One's complement: 64,626 (16-bit)

In other bases

ternary (3) 1020200

quaternary (4) 32031

quinary (5) 12114

senary (6) 4113

septenary (7) 2436

nonary (9) 1220

undecimal (11) 757

duodecimal (12) 639

tridecimal (13) 54c

tetradecimal (14) 48d

pentadecimal (15) 409

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ϡθʹ
Mayan (base 20): 𝋢·𝋥·𝋩
Chinese: 九百零九
Chinese (financial): 玖佰零玖

In other modern scripts

Eastern Arabic ٩٠٩ Devanagari ९०९ Bengali ৯০৯ Tamil ௯௦௯ Thai ๙๐๙ Tibetan ༩༠༩ Khmer ៩០៩ Lao ໙໐໙ Burmese ၉၀၉

Digit at this position in famous constants

π — Pi (π): Digit 909 = 9
e — Euler's number (e): Digit 909 = 2
φ — Golden ratio (φ): Digit 909 = 8
√2 — Pythagoras's (√2): Digit 909 = 3
ln 2 — Natural log of 2: Digit 909 = 6
γ — Euler-Mascheroni (γ): Digit 909 = 5

Also seen as

Hex color

#00038D

RGB(0, 3, 141)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.141.

Address: 0.0.3.141
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.141

Unspecified address (0.0.0.0/8) — "this network" placeholder.

NANP area code 909

The number 909 is an active NANP area code (North American Numbering Plan).

Primary area: San Bernardino / Riverside
Region: California
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.

Look up area code 909 ↗