Number

397

397 is a prime, odd, a calendar year.

397 (three 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 CCCXCVII and in binary, 110001101.

Arithmetic Number Centered Hexagonal Cousin Prime Cuban Prime Cube-Free Deficient Number Happy Number Left-Truncatable Prime Odious Number Pernicious Number Prime Pythagorean Prime Recamán's Sequence Squarefree Year

Interestingness

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11 notable facts · grade A

385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409

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Historical context — 397 AD

Calendar year

Year 397 (CCCXCVII) was a common year starting on Thursday of the Julian calendar.

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

Historical context — 397 BC

Calendar year

Year 397 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: Wednesday
January 1, 397
Ended on: Wednesday
December 31, 397
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 390s
390–399
Century: 4th century
301–400
Millennium: 1st millennium
1–1000
Years ago: 1,629
1629 years before 2026.

In other calendars

Hebrew: 4157 / 4158 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Rooster
Sexagenary cycle position 34 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 940 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 389 / 390 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 319 / 318 Saka
Indian national calendar; year starts in March.

Properties

Parity: Odd
Digit count: 3
Digit sum: 19
Digit product: 189
Digital root: 1
Palindrome: No
Bit width: 9 bits
Reversed: 793
Recamán's sequence: a(2,458) = 397
Square (n²): 157,609
Cube (n³): 62,570,773
Divisor count: 2
σ(n) — sum of divisors: 398
φ(n) — Euler's totient: 396

Primality

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

Divisors & multiples

All divisors (2)

1 · 397

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 397)

1 × 397

First multiples

397 · 794 (double) · 1,191 · 1,588 · 1,985 · 2,382 · 2,779 · 3,176 · 3,573 · 3,970

Sums & aliquot sequence

As a sum of two squares: 6² + 19²

As consecutive integers: 198 + 199

Continued fraction of √n

√397 = [19; (1, 12, 3, 4, 9, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 9, 4, 3, 12, 1, 38)]

Period length 21 — the block in parentheses repeats forever.

Representations

In words: three hundred ninety-seven
Ordinal: 397th
Roman numeral: CCCXCVII
Binary: 110001101
Octal: 615
Hexadecimal: 0x18D
Base64: AY0=
One's complement: 65,138 (16-bit)
Scientific notation: 3.97 × 10²
As a duration: 397 s = 6 minutes, 37 seconds

In other bases

ternary (3) 112201

quaternary (4) 12031

quinary (5) 3042

senary (6) 1501

septenary (7) 1105

nonary (9) 481

undecimal (11) 331

duodecimal (12) 291

tridecimal (13) 247

tetradecimal (14) 205

pentadecimal (15) 1b7

As an angle

397° = 1 × 360° + 37°

37° ≈ 0.646 rad

Compass bearing: NE (northeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): τϟζʹ
Mayan (base 20): 𝋳·𝋱
Chinese: 三百九十七
Chinese (financial): 參佰玖拾柒

In other modern scripts

Eastern Arabic ٣٩٧ Devanagari ३९७ Bengali ৩৯৭ Tamil ௩௯௭ Thai ๓๙๗ Tibetan ༣༩༧ Khmer ៣៩៧ Lao ໓໙໗ Burmese ၃၉၇

Digit at this position in famous constants

π — Pi (π): Digit 397 = 1
e — Euler's number (e): Digit 397 = 0
φ — Golden ratio (φ): Digit 397 = 7
√2 — Pythagoras's (√2): Digit 397 = 8
ln 2 — Natural log of 2: Digit 397 = 0
γ — Euler-Mascheroni (γ): Digit 397 = 9

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 389 (gap of 8)
Next prime: 401 (gap of 4)

Pair status: cousin with 401.

Unicode codepoint

Latin Small Letter Turned Delta

U+018D

Lowercase letter (Ll)

UTF-8 encoding: C6 8D (2 bytes).

Lookup U+018D on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00018D

RGB(0, 1, 141)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.141.

Address: 0.0.1.141
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.1.141

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

Musical pitch

Heard as a frequency, 397 Hz is closest to:

Concert pitch (A4 = 440 Hz): G4 (392 Hz, +22¢)
Scientific pitch (C4 = 256 Hz): G♯4 (406.4 Hz, -40¢)
Baroque pitch (A4 = 415 Hz): G♯4 (391.7 Hz, +23¢)