Number

197

197 is a prime, odd, a calendar year.

197 (one hundred ninety-seven) is an odd 3-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is CXCVII and in binary, 11000101.

Arithmetic Number Chen Prime Circular Prime Cousin Prime Cube-Free Deficient Number Evil Number Keith Number Left-Truncatable Prime Prime Pythagorean Prime Recamán's Sequence Sexy Prime Squarefree Twin Prime Year

Interestingness

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13 notable facts · grade A

185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209

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Historical context — 197 AD

Calendar year

Year 197 (CXCVII) was a common year starting on Saturday of the Julian calendar.

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

Historical context — 197 BC

Calendar year

Year 197 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: Sunday
January 1, 197
Ended on: Sunday
December 31, 197
Friday the 13ths: 2
2 Friday the 13ths this year.
Decade: 190s
190–199
Century: 2nd century
101–200
Millennium: 1st millennium
1–1000
Years ago: 1,829
1829 years before 2026.

In other calendars

Hebrew: 3957 / 3958 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Ox
Sexagenary cycle position 14 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 740 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 189 / 190 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 119 / 118 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 17
Digit product: 63
Digital root: 8
Palindrome: No
Bit width: 8 bits
Reversed: 791
Recamán's sequence: a(1,377) = 197
Square (n²): 38,809
Cube (n³): 7,645,373
Divisor count: 2
σ(n) — sum of divisors: 198
φ(n) — Euler's totient: 196

Primality

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

Divisors & multiples

All divisors (2)

1 · 197

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 197)

1 × 197

First multiples

197 · 394 (double) · 591 · 788 · 985 · 1,182 · 1,379 · 1,576 · 1,773 · 1,970

Sums & aliquot sequence

As a sum of two squares: 1² + 14²

As consecutive integers: 98 + 99

Continued fraction of √n

√197 = [14; (28)]

Period length 1 — the block in parentheses repeats forever.

Representations

In words: one hundred ninety-seven
Ordinal: 197th
Roman numeral: CXCVII
Binary: 11000101
Octal: 305
Hexadecimal: 0xC5
Base64: xQ==
One's complement: 58 (8-bit)
Scientific notation: 1.97 × 10²
As a duration: 197 s = 3 minutes, 17 seconds

In other bases

ternary (3) 21022

quaternary (4) 3011

quinary (5) 1242

senary (6) 525

septenary (7) 401

nonary (9) 238

undecimal (11) 16a

duodecimal (12) 145

tridecimal (13) 122

tetradecimal (14) 101

pentadecimal (15) d2

Palindromic in base 6, base 14

As an angle

197°

197° ≈ 3.438 rad

Compass bearing: SSW (south-southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ρϟζʹ
Mayan (base 20): 𝋩·𝋱
Chinese: 一百九十七
Chinese (financial): 壹佰玖拾柒

In other modern scripts

Eastern Arabic ١٩٧ Devanagari १९७ Bengali ১৯৭ Tamil ௧௯௭ Thai ๑๙๗ Tibetan ༡༩༧ Khmer ១៩៧ Lao ໑໙໗ Burmese ၁၉၇

Digit at this position in famous constants

π — Pi (π): Digit 197 = 3
e — Euler's number (e): Digit 197 = 0
φ — Golden ratio (φ): Digit 197 = 2
√2 — Pythagoras's (√2): Digit 197 = 5
ln 2 — Natural log of 2: Digit 197 = 1
γ — Euler-Mascheroni (γ): Digit 197 = 0

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 193 (gap of 4)
Next prime: 199 (gap of 2)

Pair status: twin with 199, cousin with 193.

Unicode codepoint

Latin Capital Letter A With Ring Above

U+00C5

Uppercase letter (Lu)

UTF-8 encoding: C3 85 (2 bytes).

Lookup U+00C5 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0000C5

RGB(0, 0, 197)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.197.

Address: 0.0.0.197
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.197

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

Musical pitch

Heard as a frequency, 197 Hz is closest to:

Concert pitch (A4 = 440 Hz): G3 (196 Hz, +9¢)
Scientific pitch (C4 = 256 Hz): G3 (191.8 Hz, +46¢ — about midway to G♯3)
Baroque pitch (A4 = 415 Hz): G♯3 (195.9 Hz, +10¢)