Number

166

166 is a composite number, even, a calendar year.

Arithmetic Number Deficient Number Evil Number Flippable Recamán's Sequence Semiprime Smith Number Squarefree Year

Historical context — 166 AD

Calendar year

Year 166 (CLXVI) was a common year starting on Tuesday of the Julian calendar.

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Historical context — 166 BC

Calendar year

Year 166 BC was a year of the pre-Julian Roman calendar.

Excerpt from Wikipedia (en) ↗ · Licensed CC BY-SA 4.0 · English fallback 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, 166
Ended on: Wednesday
December 31, 166
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 160s
160–169
Century: 2nd century
101–200
Millennium: 1st millennium
1–1000
Years ago: 1,860
1860 years before 2026.

In other calendars

Hebrew: 3926 / 3927 AM
Rosh Hashanah falls in September/October.
Chinese: Year of the zodiac:Fire zodiac:Horse
Sexagenary cycle position 43 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 709 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian: 158 / 159 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 88 / 87 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 13
Digit product: 36
Digital root: 4
Palindrome: No
Bit width: 8 bits
Reversed: 661
Flips to (rotate 180°): 991
Recamán's sequence: a(335) = 166
Square (n²): 27,556
Cube (n³): 4,574,296
Divisor count: 4
σ(n) — sum of divisors: 252
φ(n) — Euler's totient: 82
Sum of prime factors: 85

Primality

Prime factorization: 2 × 83

Nearest primes: 163 (−3) · 167 (+1)

Divisors & multiples

All divisors (4)

1 · 2 · 83 (half) · 166

Aliquot sum (sum of proper divisors): 86

Factor pairs (a × b = 166)

1 × 166

2 × 83

First multiples

166 · 332 (double) · 498 · 664 · 830 · 996 · 1,162 · 1,328 · 1,494 · 1,660

Sums & aliquot sequence

As consecutive integers: 40 + 41 + 42 + 43

Aliquot sequence: 166 → 86 → 46 → 26 → 16 → 15 → 9 → 4 → 3 → 1 → 0 — terminates at zero

Representations

In words: one hundred sixty-six
Ordinal: 166th
Roman numeral: CLXVI
Binary: 10100110
Octal: 246
Hexadecimal: 0xA6
Base64: pg==
One's complement: 89 (8-bit)

In other bases

ternary (3) 20011

quaternary (4) 2212

quinary (5) 1131

senary (6) 434

septenary (7) 325

nonary (9) 204

undecimal (11) 141

duodecimal (12) 11a

tridecimal (13) ca

tetradecimal (14) bc

pentadecimal (15) b1

Historical numeral systems

Babylonian (base 60): 𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic: 𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian): ρξϛʹ
Mayan (base 20): 𝋨·𝋦
Chinese: 一百六十六
Chinese (financial): 壹佰陸拾陸

In other modern scripts

Eastern Arabic ١٦٦ Devanagari १६६ Bengali ১৬৬ Tamil ௧௬௬ Thai ๑๖๖ Tibetan ༡༦༦ Khmer ១៦៦ Lao ໑໖໖ Burmese ၁၆၆

Digit at this position in famous constants

π — Pi (π): Digit 166 = 2
e — Euler's number (e): Digit 166 = 8
φ — Golden ratio (φ): Digit 166 = 6
√2 — Pythagoras's (√2): Digit 166 = 5
ln 2 — Natural log of 2: Digit 166 = 0
γ — Euler-Mascheroni (γ): Digit 166 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 166, here are decompositions:

3 + 163 = 166
17 + 149 = 166
29 + 137 = 166
53 + 113 = 166
59 + 107 = 166
83 + 83 = 166

Unicode codepoint

Broken Bar

U+00A6

Other symbol (So)

UTF-8 encoding: C2 A6 (2 bytes).

Lookup U+00A6 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0000A6

RGB(0, 0, 166)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.166.

Address: 0.0.0.166
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.0.166

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