Number

1,872

1,872 is a composite number, even, a calendar year.

1,872 (one thousand eight hundred seventy-two) is an even 4-digit number. It is a composite number with 30 divisors, and factors as 2⁴ × 3² × 13. Its proper divisors sum to 3,770, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCCCLXXII and in binary, 11101010000.

Abundant Number Gapful Number Harshad / Niven Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number Smith Number Year

Interestingness

★ ★ ★ ★ ☆

6 notable facts · grade B

1,860 1,861 1,862 1,863 1,864 1,865 1,866 1,867 1,868 1,869 1,870 1,871 1,872 1,873 1,874 1,875 1,876 1,877 1,878 1,879 1,880 1,881 1,882 1,883 1,884

less more

Notable events — 1872 AD

Mar 1 Yellowstone becomes the world's first national park.
Nov 5 Susan B. Anthony illegally casts a vote in the US presidential election; Grant wins re-election.
Nov 9 The Great Boston Fire of 1872 destroys 65 acres of downtown.
Apr 2 Inventor Samuel F. B. Morse dies in New York.
Dec 5 The Mary Celeste is found drifting and abandoned in the Atlantic.

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: Monday
January 1, 1872
Ended on: Tuesday
December 31, 1872
Friday the 13ths: 2
2 Friday the 13ths this year.
Easter Sunday: March 31
Sunday, March 31, 1872
Decade: 1870s
1870–1879
Century: 19th century
1801–1900
Millennium: 2nd millennium
1001–2000
Years ago: 154
154 years before 2026.
US presidential election: Yes
US holds a presidential election in years divisible by 4 starting from 1788.

In other calendars

Hebrew: 5632 / 5633 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1288 / 1289 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Water zodiac:Monkey
Sexagenary cycle position 9 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 2415 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1250 / 1251 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1864 / 1865 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1794 / 1793 Saka
Indian national calendar; year starts in March.
Japanese: Meiji 5
Reign-era counting from the start of each emperor's reign.

Properties

Parity: Even
Digit count: 4
Digit sum: 18
Digit product: 112
Digital root: 9
Palindrome: No
Bit width: 11 bits
Reversed: 2,781
Recamán's sequence: a(8,000) = 1,872
Square (n²): 3,504,384
Cube (n³): 6,560,206,848
Divisor count: 30
σ(n) — sum of divisors: 5,642
φ(n) — Euler's totient: 576
Sum of prime factors: 27

Primality

Prime factorization: 2 ⁴ × 3 ² × 13

Nearest primes: 1,871 (−1) · 1,873 (+1)

Divisors & multiples

All divisors (30)

1 · 2 · 3 · 4 · 6 · 8 · 9 · 12 · 13 · 16 · 18 · 24 · 26 · 36 · 39 · 48 · 52 · 72 · 78 · 104 · 117 · 144 · 156 · 208 · 234 · 312 · 468 · 624 · 936 (half) · 1872

Aliquot sum (sum of proper divisors): 3,770

Factor pairs (a × b = 1,872)

1 × 1872

2 × 936

3 × 624

4 × 468

6 × 312

8 × 234

9 × 208

12 × 156

13 × 144

16 × 117

18 × 104

24 × 78

26 × 72

36 × 52

39 × 48

First multiples

1,872 · 3,744 (double) · 5,616 · 7,488 · 9,360 · 11,232 · 13,104 · 14,976 · 16,848 · 18,720

Sums & aliquot sequence

As a sum of two squares: 24² + 36²

As consecutive integers: 623 + 624 + 625 204 + 205 + … + 212 138 + 139 + … + 150 43 + 44 + … + 74

Aliquot sequence: 1,872 → 3,770 → 3,790 → 3,050 → 2,716 → 2,772 → 5,964 → 10,164 → 19,628 → 19,684 → 22,876 → 26,404 → 30,044 → 33,796 → 38,780 → 54,628 → 54,684 — unresolved within range

Continued fraction of √n

√1,872 = [43; (3, 1, 3, 86)]

Period length 4 — the block in parentheses repeats forever.

Representations

In words: one thousand eight hundred seventy-two
Ordinal: 1872nd
Roman numeral: MDCCCLXXII
Binary: 11101010000
Octal: 3520
Hexadecimal: 0x750
Base64: B1A=
One's complement: 63,663 (16-bit)
Scientific notation: 1.872 × 10³
As a duration: 1,872 s = 31 minutes, 12 seconds

In other bases

ternary (3) 2120100

quaternary (4) 131100

quinary (5) 24442

senary (6) 12400

septenary (7) 5313

nonary (9) 2510

undecimal (11) 1452

duodecimal (12) 1100

tridecimal (13) b10

tetradecimal (14) 97a

pentadecimal (15) 84c

Palindromic in base 5

As an angle

1,872° = 5 × 360° + 72°

72° ≈ 1.257 rad

Compass bearing: ENE (east-northeast)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒁹 𒌋𒁹𒁹
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓏺𓏺
Greek (Milesian): ͵αωοβʹ
Mayan (base 20): 𝋤·𝋭·𝋬
Chinese: 一千八百七十二
Chinese (financial): 壹仟捌佰柒拾貳

In other modern scripts

Eastern Arabic ١٨٧٢ Devanagari १८७२ Bengali ১৮৭২ Tamil ௧௮௭௨ Thai ๑๘๗๒ Tibetan ༡༨༧༢ Khmer ១៨៧២ Lao ໑໘໗໒ Burmese ၁၈၇၂

Digit at this position in famous constants

π — Pi (π): Digit 1,872 = 2
e — Euler's number (e): Digit 1,872 = 2
φ — Golden ratio (φ): Digit 1,872 = 7
√2 — Pythagoras's (√2): Digit 1,872 = 8
ln 2 — Natural log of 2: Digit 1,872 = 0
γ — Euler-Mascheroni (γ): Digit 1,872 = 0

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1872, here are decompositions:

5 + 1867 = 1872
11 + 1861 = 1872
41 + 1831 = 1872
61 + 1811 = 1872
71 + 1801 = 1872
83 + 1789 = 1872
89 + 1783 = 1872
113 + 1759 = 1872

Showing the first eight; more decompositions exist.

Unicode codepoint

Arabic Letter Beh With Three Dots Horizontally Below

U+0750

Other letter (Lo)

UTF-8 encoding: DD 90 (2 bytes).

Lookup U+0750 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000750

RGB(0, 7, 80)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.7.80.

Address: 0.0.7.80
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.7.80

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

Musical pitch

Heard as a frequency, 1,872 Hz is closest to:

Concert pitch (A4 = 440 Hz): A♯6 (1864.7 Hz, +7¢)
Scientific pitch (C4 = 256 Hz): A♯6 (1824.6 Hz, +44¢)
Baroque pitch (A4 = 415 Hz): B6 (1863.3 Hz, +8¢)

Position in π

The digit sequence 1872 first appears in π at position 7,292 of the decimal expansion (the 7,292ordinal-suffix:nd 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 1872 on Pi Search ↗