Number

247

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

247 (two hundred forty-seven) is an odd 3-digit number. It is a composite number with 4 divisors, and factors as 13 × 19. Written other ways, in Roman numerals it is CCXLVII and in binary, 11110111.

Arithmetic Number Ascending Digits Cube-Free Deficient Number Harshad / Niven Moran Number Odious Number Pentagonal Pernicious Number Recamán's Sequence Semiprime Squarefree Year

Interestingness

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9 notable facts · grade A

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Historical context — 247 AD

Calendar year

Year 247 (CCXLVII) was a common year starting on Friday of the Julian calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →

Historical context — 247 BC

Calendar year

Year 247 BC was a year of the pre-Julian Roman calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 Read the full article on Wikipedia →

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: Friday
January 1, 247
Ended on: Friday
December 31, 247
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 240s
240–249
Century: 3rd century
201–300
Millennium: 1st millennium
1–1000
Years ago: 1,779
1779 years before 2026.

In other calendars

Hebrew: 4007 / 4008 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Rabbit
Sexagenary cycle position 4 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 790 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 239 / 240 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 169 / 168 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 13
Digit product: 56
Digital root: 4
Palindrome: No
Bit width: 8 bits
Reversed: 742
Recamán's sequence: a(249) = 247
Square (n²): 61,009
Cube (n³): 15,069,223
Divisor count: 4
σ(n) — sum of divisors: 280
φ(n) — Euler's totient: 216
Sum of prime factors: 32

Primality

Prime factorization: 13 × 19

Nearest primes: 241 (−6) · 251 (+4)

Divisors & multiples

All divisors (4)

1 · 13 · 19 · 247

Aliquot sum (sum of proper divisors): 33

Factor pairs (a × b = 247)

1 × 247

13 × 19

First multiples

247 · 494 (double) · 741 · 988 · 1,235 · 1,482 · 1,729 · 1,976 · 2,223 · 2,470

Sums & aliquot sequence

As consecutive integers: 123 + 124 13 + 14 + … + 25 4 + 5 + … + 22

Aliquot sequence: 247 → 33 → 15 → 9 → 4 → 3 → 1 → 0 — terminates at zero

Continued fraction of √n

√247 = [15; (1, 2, 1, 1, 9, 1, 9, 1, 1, 2, 1, 30)]

Period length 12 — the block in parentheses repeats forever.

Representations

In words: two hundred forty-seven
Ordinal: 247th
Roman numeral: CCXLVII
Binary: 11110111
Octal: 367
Hexadecimal: 0xF7
Base64: 9w==
One's complement: 8 (8-bit)
Scientific notation: 2.47 × 10²
As a duration: 247 s = 4 minutes, 7 seconds

In other bases

ternary (3) 100011

quaternary (4) 3313

quinary (5) 1442

senary (6) 1051

septenary (7) 502

nonary (9) 304

undecimal (11) 205

duodecimal (12) 187

tridecimal (13) 160

tetradecimal (14) 139

pentadecimal (15) 117

As an angle

247°

247° ≈ 4.311 rad

Compass bearing: WSW (west-southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): σμζʹ
Mayan (base 20): 𝋬·𝋧
Chinese: 二百四十七
Chinese (financial): 貳佰肆拾柒

In other modern scripts

Eastern Arabic ٢٤٧ Devanagari २४७ Bengali ২৪৭ Tamil ௨௪௭ Thai ๒๔๗ Tibetan ༢༤༧ Khmer ២៤៧ Lao ໒໔໗ Burmese ၂၄၇

Digit at this position in famous constants

π — Pi (π): Digit 247 = 1
e — Euler's number (e): Digit 247 = 0
φ — Golden ratio (φ): Digit 247 = 6
√2 — Pythagoras's (√2): Digit 247 = 9
ln 2 — Natural log of 2: Digit 247 = 4
γ — Euler-Mascheroni (γ): Digit 247 = 1

Also seen as

Unicode codepoint

Division Sign

U+00F7

Math symbol (Sm)

UTF-8 encoding: C3 B7 (2 bytes).

Lookup U+00F7 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0000F7

RGB(0, 0, 247)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.247.

Address: 0.0.0.247
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.247

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

Musical pitch

Heard as a frequency, 247 Hz is closest to:

Concert pitch (A4 = 440 Hz): B3 (246.9 Hz, exact)
Scientific pitch (C4 = 256 Hz): B3 (241.6 Hz, +38¢)
Baroque pitch (A4 = 415 Hz): C4 (246.8 Hz, +2¢)