Number

243

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

Deficient Number Evil Number Harshad / Niven Powerful Number Recamán's Sequence Year

Historical context — 243 AD

Calendar year

Year 243 (CCXLIII) was a common year starting on Sunday of the Julian calendar.

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Historical context — 243 BC

Calendar year

Year 243 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: Sunday
January 1, 243
Ended on: Sunday
December 31, 243
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 240s
240–249
Century: 3rd century
201–300
Millennium: 1st millennium
1–1000
Years ago: 1,783
1783 years before 2026.

In other calendars

Hebrew: 4003 / 4004 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Water zodiac:Pig
Sexagenary cycle position 60 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 786 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 235 / 236 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 165 / 164 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 9
Digit product: 24
Digital root: 9
Palindrome: No
Bit width: 8 bits
Reversed: 342
Recamán's sequence: a(257) = 243
Square (n²): 59,049
Cube (n³): 14,348,907
Divisor count: 6
σ(n) — sum of divisors: 364
φ(n) — Euler's totient: 162
Sum of prime factors: 15

Primality

Prime factorization: 3 ⁵

Nearest primes: 241 (−2) · 251 (+8)

Divisors & multiples

All divisors (6)

1 · 3 · 9 · 27 · 81 · 243

Aliquot sum (sum of proper divisors): 121

Factor pairs (a × b = 243)

1 × 243

3 × 81

9 × 27

First multiples

243 · 486 (double) · 729 · 972 · 1,215 · 1,458 · 1,701 · 1,944 · 2,187 · 2,430

Sums & aliquot sequence

As consecutive integers: 121 + 122 80 + 81 + 82 38 + 39 + 40 + 41 + 42 + 43 23 + 24 + … + 31

Aliquot sequence: 243 → 121 → 12 → 16 → 15 → 9 → 4 → 3 → 1 → 0 — terminates at zero

Representations

In words: two hundred forty-three
Ordinal: 243rd
Roman numeral: CCXLIII
Binary: 11110011
Octal: 363
Hexadecimal: 0xF3
Base64: 8w==
One's complement: 12 (8-bit)

In other bases

ternary (3) 100000

quaternary (4) 3303

quinary (5) 1433

senary (6) 1043

septenary (7) 465

nonary (9) 300

undecimal (11) 201

duodecimal (12) 183

tridecimal (13) 159

tetradecimal (14) 135

pentadecimal (15) 113

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹 𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺
Greek (Milesian): σμγʹ
Mayan (base 20): 𝋬·𝋣
Chinese: 二百四十三
Chinese (financial): 貳佰肆拾參

In other modern scripts

Eastern Arabic ٢٤٣ Devanagari २४३ Bengali ২৪৩ Tamil ௨௪௩ Thai ๒๔๓ Tibetan ༢༤༣ Khmer ២៤៣ Lao ໒໔໓ Burmese ၂၄၃

Digit at this position in famous constants

π — Pi (π): Digit 243 = 7
e — Euler's number (e): Digit 243 = 6
φ — Golden ratio (φ): Digit 243 = 4
√2 — Pythagoras's (√2): Digit 243 = 4
ln 2 — Natural log of 2: Digit 243 = 2
γ — Euler-Mascheroni (γ): Digit 243 = 9

Also seen as

Unicode codepoint

Latin Small Letter O With Acute

U+00F3

Lowercase letter (Ll)

UTF-8 encoding: C3 B3 (2 bytes).

Lookup U+00F3 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0000F3

RGB(0, 0, 243)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.243.

Address: 0.0.0.243
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.243

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