Number

1,998

1,998 is a composite number, even, a calendar year.

1,998 (one thousand nine hundred ninety-eight) is an even 4-digit number. It is a composite number with 16 divisors, and factors as 2 × 3³ × 37. Its proper divisors sum to 2,562, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MCMXCVIII and in binary, 11111001110.

Abundant Number Arithmetic Number Evil Number Flippable Gapful Number Harshad / Niven Practical Number Recamán's Sequence Semiperfect Number Year

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

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 2,010

less more

Notable events — 1998 AD

Feb 7 The Winter Olympics open in Nagano, Japan.
May 11 India conducts a series of underground nuclear tests (Pokhran-II).
Aug 7 Simultaneous truck bombs destroy US embassies in Kenya and Tanzania.
Sep 4 Larry Page and Sergey Brin incorporate Google in Menlo Park, California.
Dec 19 President Bill Clinton is impeached by the US House of Representatives.

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: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 1998
Ended on: Thursday
December 31, 1998
Friday the 13ths: 3
3 Friday the 13ths this year.
Easter Sunday: April 12
Sunday, April 12, 1998
Decade: 1990s
1990–1999
Century: 20th century
1901–2000
Millennium: 2nd millennium
1001–2000
Years ago: 28
28 years before 2026.
FIFA World Cup: Yes
Men's FIFA World Cup is held every four years (skipped 1942 and 1946 due to WWII).
Winter Olympics: Yes
Held in even years between Summer Games (2002, 2006, ...).

In other calendars

Hebrew: 5758 / 5759 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1418 / 1419 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Earth zodiac:Tiger
Sexagenary cycle position 15 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 2541 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1376 / 1377 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1990 / 1991 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1920 / 1919 Saka
Indian national calendar; year starts in March.
Japanese: Heisei 10
Reign-era counting from the start of each emperor's reign.

Properties

Parity: Even
Digit count: 4
Digit sum: 27
Digit product: 648
Digital root: 9
Palindrome: No
Bit width: 11 bits
Reversed: 8,991
Flips to (rotate 180°): 8,661
Recamán's sequence: a(3,755) = 1,998
Square (n²): 3,992,004
Cube (n³): 7,976,023,992
Divisor count: 16
σ(n) — sum of divisors: 4,560
φ(n) — Euler's totient: 648
Sum of prime factors: 48

Primality

Prime factorization: 2 × 3 ³ × 37

Nearest primes: 1,997 (−1) · 1,999 (+1)

Divisors & multiples

All divisors (16)

1 · 2 · 3 · 6 · 9 · 18 · 27 · 37 · 54 · 74 · 111 · 222 · 333 · 666 · 999 (half) · 1998

Aliquot sum (sum of proper divisors): 2,562

Factor pairs (a × b = 1,998)

1 × 1998

2 × 999

3 × 666

6 × 333

9 × 222

18 × 111

27 × 74

37 × 54

First multiples

1,998 · 3,996 (double) · 5,994 · 7,992 · 9,990 · 11,988 · 13,986 · 15,984 · 17,982 · 19,980

Sums & aliquot sequence

As consecutive integers: 665 + 666 + 667 498 + 499 + 500 + 501 218 + 219 + … + 226 161 + 162 + … + 172

Aliquot sequence: 1,998 → 2,562 → 3,390 → 4,818 → 5,838 → 7,602 → 9,870 → 17,778 → 17,790 → 24,978 → 27,438 → 30,882 → 30,894 → 34,386 → 40,782 → 52,530 → 82,254 — unresolved within range

Continued fraction of √n

√1,998 = [44; (1, 2, 3, 9, 1, 1, 1, 2, 1, 1, 1, 9, 3, 2, 1, 88)]

Period length 16 — the block in parentheses repeats forever.

Representations

In words: one thousand nine hundred ninety-eight
Ordinal: 1998th
Roman numeral: MCMXCVIII
Binary: 11111001110
Octal: 3716
Hexadecimal: 0x7CE
Base64: B84=
One's complement: 63,537 (16-bit)
Scientific notation: 1.998 × 10³
As a duration: 1,998 s = 33 minutes, 18 seconds

In other bases

ternary (3) 2202000

quaternary (4) 133032

quinary (5) 30443

senary (6) 13130

septenary (7) 5553

nonary (9) 2660

undecimal (11) 1557

duodecimal (12) 11a6

tridecimal (13) ba9

tetradecimal (14) a2a

pentadecimal (15) 8d3

Palindromic in base 14

As an angle

1,998° = 5 × 360° + 198°

198° ≈ 3.456 rad

Compass bearing: SSW (south-southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ͵αϡϟηʹ
Mayan (base 20): 𝋤·𝋳·𝋲
Chinese: 一千九百九十八
Chinese (financial): 壹仟玖佰玖拾捌

In other modern scripts

Eastern Arabic ١٩٩٨ Devanagari १९९८ Bengali ১৯৯৮ Tamil ௧௯௯௮ Thai ๑๙๙๘ Tibetan ༡༩༩༨ Khmer ១៩៩៨ Lao ໑໙໙໘ Burmese ၁၉၉၈

Digit at this position in famous constants

π — Pi (π): Digit 1,998 = 9
e — Euler's number (e): Digit 1,998 = 8
φ — Golden ratio (φ): Digit 1,998 = 3
√2 — Pythagoras's (√2): Digit 1,998 = 6
ln 2 — Natural log of 2: Digit 1,998 = 0
γ — Euler-Mascheroni (γ): Digit 1,998 = 2

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1998, here are decompositions:

5 + 1993 = 1998
11 + 1987 = 1998
19 + 1979 = 1998
47 + 1951 = 1998
67 + 1931 = 1998
97 + 1901 = 1998
109 + 1889 = 1998
127 + 1871 = 1998

Showing the first eight; more decompositions exist.

Unicode codepoint

Nko Letter U

U+07CE

Other letter (Lo)

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

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

Hex color

#0007CE

RGB(0, 7, 206)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.206.

Address: 0.0.7.206
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.206

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

Musical pitch

Heard as a frequency, 1,998 Hz is closest to:

Concert pitch (A4 = 440 Hz): B6 (1975.5 Hz, +20¢)
Scientific pitch (C4 = 256 Hz): C7 (2048 Hz, -43¢)
Baroque pitch (A4 = 415 Hz): C7 (1974.1 Hz, +21¢)

Position in π

The digit sequence 1998 first appears in π at position 29,888 of the decimal expansion (the 29,888ordinal-suffix:th 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 1998 on Pi Search ↗