Number

1,997

1,997 is a prime, odd, a calendar year.

1,997 (one thousand nine hundred ninety-seven) is an odd 4-digit number. It is a prime number — divisible only by 1 and itself. Written other ways, in Roman numerals it is MCMXCVII and in binary, 11111001101.

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

Interestingness

★ ★ ★ ★ ★

11 notable facts · grade A

1,985 1,986 1,987 1,988 1,989 1,990 1,991 1,992 1,993 1,994 1,995 1,996 1,997 1,998 1,999 2,000 2,001 2,002 2,003 2,004 2,005 2,006 2,007 2,008 2,009

less more

Notable events — 1997 AD

Mar 22 Comet Hale-Bopp makes its closest approach to Earth.
Mar 26 39 members of the Heaven's Gate cult commit mass suicide in San Diego.
May 11 IBM's Deep Blue defeats world chess champion Garry Kasparov.
Jul 1 The United Kingdom transfers sovereignty of Hong Kong to China.
Aug 31 Diana, Princess of Wales, dies in a car crash in Paris.

Events compiled from Wikipedia ↗ · Licensed CC BY-SA 4.0

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, 1997
Ended on: Wednesday
December 31, 1997
Friday the 13ths: 1
One Friday the 13th this year.
Easter Sunday: March 30
Sunday, March 30, 1997
Decade: 1990s
1990–1999
Century: 20th century
1901–2000
Millennium: 2nd millennium
1001–2000
Years ago: 29
29 years before 2026.

In other calendars

Hebrew: 5757 / 5758 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1417 / 1418 AH
Lunar calendar; year spans differ from Gregorian.
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: 2540 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1375 / 1376 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1989 / 1990 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1919 / 1918 Saka
Indian national calendar; year starts in March.
Japanese: Heisei 9
Reign-era counting from the start of each emperor's reign.

Properties

Parity: Odd
Digit count: 4
Digit sum: 26
Digit product: 567
Digital root: 8
Palindrome: No
Bit width: 11 bits
Reversed: 7,991
Recamán's sequence: a(3,757) = 1,997
Square (n²): 3,988,009
Cube (n³): 7,964,053,973
Divisor count: 2
σ(n) — sum of divisors: 1,998
φ(n) — Euler's totient: 1,996

Primality

1,997 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)

1 · 1997

Aliquot sum (sum of proper divisors): 1

Factor pairs (a × b = 1,997)

1 × 1997

First multiples

1,997 · 3,994 (double) · 5,991 · 7,988 · 9,985 · 11,982 · 13,979 · 15,976 · 17,973 · 19,970

Sums & aliquot sequence

As a sum of two squares: 29² + 34²

As consecutive integers: 998 + 999

Continued fraction of √n

√1,997 = [44; (1, 2, 4, 1, 11, 1, 21, 2, 2, 1, 2, 2, 1, 2, 2, 21, 1, 11, 1, 4, 2, 1, 88)]

Period length 23 — the block in parentheses repeats forever.

Representations

In words: one thousand nine hundred ninety-seven
Ordinal: 1997th
Roman numeral: MCMXCVII
Binary: 11111001101
Octal: 3715
Hexadecimal: 0x7CD
Base64: B80=
One's complement: 63,538 (16-bit)
Scientific notation: 1.997 × 10³
As a duration: 1,997 s = 33 minutes, 17 seconds

In other bases

ternary (3) 2201222

quaternary (4) 133031

quinary (5) 30442

senary (6) 13125

septenary (7) 5552

nonary (9) 2658

undecimal (11) 1556

duodecimal (12) 11a5

tridecimal (13) ba8

tetradecimal (14) a29

pentadecimal (15) 8d2

As an angle

1,997° = 5 × 360° + 197°

197° ≈ 3.438 rad

Compass bearing: SSW (south-southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵αϡϟζʹ
Mayan (base 20): 𝋤·𝋳·𝋱
Chinese: 一千九百九十七
Chinese (financial): 壹仟玖佰玖拾柒

In other modern scripts

Eastern Arabic ١٩٩٧ Devanagari १९९७ Bengali ১৯৯৭ Tamil ௧௯௯௭ Thai ๑๙๙๗ Tibetan ༡༩༩༧ Khmer ១៩៩៧ Lao ໑໙໙໗ Burmese ၁၉၉၇

Digit at this position in famous constants

π — Pi (π): Digit 1,997 = 5
e — Euler's number (e): Digit 1,997 = 9
φ — Golden ratio (φ): Digit 1,997 = 1
√2 — Pythagoras's (√2): Digit 1,997 = 3
ln 2 — Natural log of 2: Digit 1,997 = 7
γ — Euler-Mascheroni (γ): Digit 1,997 = 6

Also seen as

Prime neighborhood

Adjacent primes:

Previous prime: 1,993 (gap of 4)
Next prime: 1,999 (gap of 2)

Pair status: twin with 1999, cousin with 1993.

Unicode codepoint

Nko Letter E

U+07CD

Other letter (Lo)

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

Lookup U+07CD on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0007CD

RGB(0, 7, 205)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.205.

Address: 0.0.7.205
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.205

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

Musical pitch

Heard as a frequency, 1,997 Hz is closest to:

Concert pitch (A4 = 440 Hz): B6 (1975.5 Hz, +19¢)
Scientific pitch (C4 = 256 Hz): C7 (2048 Hz, -44¢)
Baroque pitch (A4 = 415 Hz): C7 (1974.1 Hz, +20¢)

Position in π

The digit sequence 1997 first appears in π at position 30,171 of the decimal expansion (the 30,171ordinal-suffix:st digit after the integer 3).

Search range: the first 1,000,000 fractional digits of π. Any 6-digit-or-shorter string is virtually guaranteed to appear in there — the more interesting signal is the position.

Look up 1997 on Pi Search ↗