198
198 is a composite number, even, a calendar year.
198 (one hundred ninety-eight) is an even 3-digit number. It is a composite number with 12 divisors, and factors as 2 × 3² × 11. Its proper divisors sum to 270, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is CXCVIII and in binary, 11000110.
Interestingness
Historical context — 198 AD
Calendar year
Year 198 (CXCVIII) was a common year starting on Sunday of the Julian calendar.
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Historical context — 198 BC
Calendar year
Year 198 BC was a year of the pre-Julian Roman calendar.
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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
-
Monday
January 1, 198
- Ended on
-
Monday
December 31, 198
- 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
-
1,828
1828 years before 2026.
In other calendars
- Hebrew
-
3958 / 3959 AM
Rosh Hashanah falls in September/October.
- 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
-
741 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
190 / 191 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
120 / 119 Saka
Indian national calendar; year starts in March.
Properties
- Parity
- Even
- Digit count
- 3
- Digit sum
- 18
- Digit product
- 72
- Digital root
- 9
- Palindrome
- No
- Bit width
- 8 bits
- Reversed
- 891
- Flips to (rotate 180°)
- 861
- Recamán's sequence
- a(1,375) = 198
- Square (n²)
- 39,204
- Cube (n³)
- 7,762,392
- Divisor count
- 12
- σ(n) — sum of divisors
- 468
- φ(n) — Euler's totient
- 60
- Sum of prime factors
- 19
Primality
Prime factorization: 2 × 3 2 × 11
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√198 = [14; (14, 28)]
Period length 2 — the block in parentheses repeats forever.
Representations
- In words
- one hundred ninety-eight
- Ordinal
- 198th
- Roman numeral
- CXCVIII
- Binary
- 11000110
- Octal
- 306
- Hexadecimal
- 0xC6
- Base64
- xg==
- One's complement
- 57 (8-bit)
- Scientific notation
- 1.98 × 10²
- As a duration
- 198 s = 3 minutes, 18 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹𒁹 𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ρϟηʹ
- Mayan (base 20)
- 𝋩·𝋲
- Chinese
- 一百九十八
- Chinese (financial)
- 壹佰玖拾捌
Digit at this position in famous constants
- π — Pi (π)
- Digit 198 = 8
- e — Euler's number (e)
- Digit 198 = 1
- φ — Golden ratio (φ)
- Digit 198 = 6
- √2 — Pythagoras's (√2)
- Digit 198 = 7
- ln 2 — Natural log of 2
- Digit 198 = 2
- γ — Euler-Mascheroni (γ)
- Digit 198 = 9
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 198, here are decompositions:
- 5 + 193 = 198
- 7 + 191 = 198
- 17 + 181 = 198
- 19 + 179 = 198
- 31 + 167 = 198
- 41 + 157 = 198
- 47 + 151 = 198
- 59 + 139 = 198
Showing the first eight; more decompositions exist.
UTF-8 encoding: C3 86 (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.198.
- Address
- 0.0.0.198
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.198
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 198 Hz is closest to:
- Concert pitch (A4 = 440 Hz): G3 (196 Hz, +18¢)
- Scientific pitch (C4 = 256 Hz): G♯3 (203.2 Hz, -45¢ — about midway to G3)
- Baroque pitch (A4 = 415 Hz): G♯3 (195.9 Hz, +19¢)
Related reading
- Babylonian numerals — The base-60 cuneiform system that gave us 60 minutes, 60 seconds, and 360°.