Number

491

491 is a prime, odd, a calendar year.

Arithmetic Number Chen Prime Cousin Prime Deficient Number Odious Number Pernicious Number Prime Recamán's Sequence Sophie Germain Prime Squarefree Year

Historical context — 491 AD

Calendar year

Year 491 (CDXCI) was a common year starting on Tuesday of the Julian calendar.

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Historical context — 491 BC

Calendar year

Year 491 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: Monday
January 1, 491
Ended on: Monday
December 31, 491
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 490s
490–499
Century: 5th century
401–500
Millennium: 1st millennium
1–1000
Years ago: 1,535
1535 years before 2026.

In other calendars

Hebrew: 4251 / 4252 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Metal zodiac:Goat
Sexagenary cycle position 8 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1034 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 483 / 484 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 413 / 412 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 14
Digit product: 36
Digital root: 5
Palindrome: No
Bit width: 9 bits
Reversed: 194
Recamán's sequence: a(230) = 491
Square (n²): 241,081
Cube (n³): 118,370,771
Divisor count: 2
σ(n) — sum of divisors: 492
φ(n) — Euler's totient: 490

Primality

491 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 491

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 491)

1 × 491

First multiples

491 · 982 (double) · 1,473 · 1,964 · 2,455 · 2,946 · 3,437 · 3,928 · 4,419 · 4,910

Sums & aliquot sequence

As consecutive integers: 245 + 246

Representations

In words: four hundred ninety-one
Ordinal: 491st
Roman numeral: CDXCI
Binary: 111101011
Octal: 753
Hexadecimal: 0x1EB
Base64: Aes=
One's complement: 65,044 (16-bit)

In other bases

ternary (3) 200012

quaternary (4) 13223

quinary (5) 3431

senary (6) 2135

septenary (7) 1301

nonary (9) 605

undecimal (11) 407

duodecimal (12) 34b

tridecimal (13) 2ba

tetradecimal (14) 271

pentadecimal (15) 22b

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺
Greek (Milesian): υϟαʹ
Mayan (base 20): 𝋡·𝋤·𝋫
Chinese: 四百九十一
Chinese (financial): 肆佰玖拾壹

In other modern scripts

Eastern Arabic ٤٩١ Devanagari ४९१ Bengali ৪৯১ Tamil ௪௯௧ Thai ๔๙๑ Tibetan ༤༩༡ Khmer ៤៩១ Lao ໔໙໑ Burmese ၄၉၁

Digit at this position in famous constants

π — Pi (π): Digit 491 = 1
e — Euler's number (e): Digit 491 = 2
φ — Golden ratio (φ): Digit 491 = 6
√2 — Pythagoras's (√2): Digit 491 = 5
ln 2 — Natural log of 2: Digit 491 = 9
γ — Euler-Mascheroni (γ): Digit 491 = 6

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 487 (gap of 4)
Next prime: 499 (gap of 8)

Pair status: cousin with 487.

Unicode codepoint

Latin Small Letter O With Ogonek

U+01EB

Lowercase letter (Ll)

UTF-8 encoding: C7 AB (2 bytes).

Lookup U+01EB on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0001EB

RGB(0, 1, 235)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.235.

Address: 0.0.1.235
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.1.235

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