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Number

168

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

Abundant Number Arithmetic Number Ascending Digits Flippable Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number Year

Historical context — 168 AD

Calendar year

Year 168 (CLXVIII) was a leap year starting on Thursday of the Julian calendar.

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

Notable events — 168 BC

  1. Jun 22 Rome decisively defeats Macedon at Pydna.

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

Year facts

Year type
Leap year
Divisible by 4 and not by 100; February has 29 days.
Days in year
366
ISO weeks
52
Started on
Friday
January 1, 168
Ended on
Saturday
December 31, 168
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
1,858
1858 years before 2026.

In other calendars

Hebrew
3928 / 3929 AM
Rosh Hashanah falls in September/October.
Chinese
Year of the zodiac:Earth zodiac:Monkey
Sexagenary cycle position 45 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era
711 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Ethiopian
160 / 161 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka)
90 / 89 Saka
Indian national calendar; year starts in March.

Properties

Parity
Even
Digit count
3
Digit sum
15
Digit product
48
Digital root
6
Palindrome
No
Bit width
8 bits
Reversed
861
Flips to (rotate 180°)
891
Recamán's sequence
a(331) = 168
Square (n²)
28,224
Cube (n³)
4,741,632
Divisor count
16
σ(n) — sum of divisors
480
φ(n) — Euler's totient
48
Sum of prime factors
16

Primality

Prime factorization: 2 3 × 3 × 7

Nearest primes: 167 (−1) · 173 (+5)

Divisors & multiples

All divisors (16)
1 · 2 · 3 · 4 · 6 · 7 · 8 · 12 · 14 · 21 · 24 · 28 · 42 · 56 · 84 (half) · 168
Aliquot sum (sum of proper divisors): 312
Factor pairs (a × b = 168)
1 × 168
2 × 84
3 × 56
4 × 42
6 × 28
7 × 24
8 × 21
12 × 14
First multiples
168 · 336 (double) · 504 · 672 · 840 · 1,008 · 1,176 · 1,344 · 1,512 · 1,680

Sums & aliquot sequence

As consecutive integers: 55 + 56 + 57 21 + 22 + … + 27 3 + 4 + … + 18
Aliquot sequence: 168 312 528 960 2,088 3,762 5,598 6,570 10,746 13,254 13,830 19,434 20,886 21,606 25,098 26,742 26,754 — unresolved within range

Representations

In words
one hundred sixty-eight
Ordinal
168th
Roman numeral
CLXVIII
Binary
10101000
Octal
250
Hexadecimal
0xA8
Base64
qA==
One's complement
87 (8-bit)
In other bases
ternary (3) 20020
quaternary (4) 2220
quinary (5) 1133
senary (6) 440
septenary (7) 330
nonary (9) 206
undecimal (11) 143
duodecimal (12) 120
tridecimal (13) cc
tetradecimal (14) c0
pentadecimal (15) b3

Historical numeral systems

Babylonian (base 60)
𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹
Egyptian hieroglyphic
𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺𓏺
Greek (Milesian)
ρξηʹ
Mayan (base 20)
𝋨·𝋨
Chinese
一百六十八
Chinese (financial)
壹佰陸拾捌
In other modern scripts
Eastern Arabic ١٦٨ Devanagari १६८ Bengali ১৬৮ Tamil ௧௬௮ Thai ๑๖๘ Tibetan ༡༦༨ Khmer ១៦៨ Lao ໑໖໘ Burmese ၁၆၈

Digit at this position in famous constants

π — Pi (π)
Digit 168 = 0
e — Euler's number (e)
Digit 168 = 2
φ — Golden ratio (φ)
Digit 168 = 9
√2 — Pythagoras's (√2)
Digit 168 = 2
ln 2 — Natural log of 2
Digit 168 = 2
γ — Euler-Mascheroni (γ)
Digit 168 = 4

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 168, here are decompositions:

  • 5 + 163 = 168
  • 11 + 157 = 168
  • 17 + 151 = 168
  • 19 + 149 = 168
  • 29 + 139 = 168
  • 31 + 137 = 168
  • 37 + 131 = 168
  • 41 + 127 = 168

Showing the first eight; more decompositions exist.

Unicode codepoint
¨
Diaeresis
U+00A8
Modifier symbol (Sk)

UTF-8 encoding: C2 A8 (2 bytes).

Hex color
#0000A8
RGB(0, 0, 168)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.168.

Address
0.0.0.168
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.0.168

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