172
172 is a composite number, even, a calendar year.
172 (one hundred seventy-two) is an even 3-digit number. It is a composite number with 6 divisors, and factors as 2² × 43. Written other ways, in Roman numerals it is CLXXII and in binary, 10101100.
Interestingness
Historical context — 172 AD
Calendar year
Year 172 (CLXXII) was a leap year starting on Tuesday of the Julian calendar.
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Historical context — 172 BC
Calendar year
Year 172 BC was a year of the pre-Julian Roman calendar.
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Year facts
- Year type
-
Leap year
Divisible by 4 and not by 100; February has 29 days.
- Days in year
- 366
- ISO weeks
-
53
Long year: contains 53 ISO weeks.
- Started on
-
Wednesday
January 1, 172
- Ended on
-
Thursday
December 31, 172
- Friday the 13ths
-
2
2 Friday the 13ths this year.
- Decade
-
170s
170–179
- Century
-
2nd century
101–200
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,854
1854 years before 2026.
In other calendars
- Hebrew
-
3932 / 3933 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Water zodiac:Rat
Sexagenary cycle position 49 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
715 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
164 / 165 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
94 / 93 Saka
Indian national calendar; year starts in March.
Properties
Primality
Prime factorization: 2 2 × 43
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√172 = [13; (8, 1, 2, 2, 1, 1, 3, 6, 3, 1, 1, 2, 2, 1, 8, 26)]
Period length 16 — the block in parentheses repeats forever.
Representations
- In words
- one hundred seventy-two
- Ordinal
- 172nd
- Roman numeral
- CLXXII
- Binary
- 10101100
- Octal
- 254
- Hexadecimal
- 0xAC
- Base64
- rA==
- One's complement
- 83 (8-bit)
- Scientific notation
- 1.72 × 10²
- As a duration
- 172 s = 2 minutes, 52 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹 𒌋𒌋𒌋𒌋𒌋𒁹𒁹
- Egyptian hieroglyphic
- 𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺
- Greek (Milesian)
- ροβʹ
- Mayan (base 20)
- 𝋨·𝋬
- Chinese
- 一百七十二
- Chinese (financial)
- 壹佰柒拾貳
Digit at this position in famous constants
- π — Pi (π)
- Digit 172 = 8
- e — Euler's number (e)
- Digit 172 = 3
- φ — Golden ratio (φ)
- Digit 172 = 9
- √2 — Pythagoras's (√2)
- Digit 172 = 5
- ln 2 — Natural log of 2
- Digit 172 = 1
- γ — Euler-Mascheroni (γ)
- Digit 172 = 7
Also seen as
Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 172, here are decompositions:
- 5 + 167 = 172
- 23 + 149 = 172
- 41 + 131 = 172
- 59 + 113 = 172
- 71 + 101 = 172
- 83 + 89 = 172
UTF-8 encoding: C2 AC (2 bytes).
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.172.
- Address
- 0.0.0.172
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.172
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 172 Hz is closest to:
- Concert pitch (A4 = 440 Hz): F3 (174.6 Hz, -26¢)
- Scientific pitch (C4 = 256 Hz): F3 (170.9 Hz, +12¢)
- Baroque pitch (A4 = 415 Hz): F♯3 (174.5 Hz, -25¢)
On an ingredients label, E172 is Iron oxides and hydroxides, a food colour.
Related reading
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.