Number

1,780

1,780 is a composite number, even, a calendar year.

1,780 (one thousand seven hundred eighty) is an even 4-digit number. It is a composite number with 12 divisors, and factors as 2² × 5 × 89. Its proper divisors sum to 2,000, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCCLXXX and in binary, 11011110100.

Abundant Number Arithmetic Number Cube-Free Gapful Number Odious Number Pernicious Number Recamán's Sequence Semiperfect Number Year

Interestingness

★ ★ ★ ☆ ☆

5 notable facts · grade C

1,768 1,769 1,770 1,771 1,772 1,773 1,774 1,775 1,776 1,777 1,778 1,779 1,780 1,781 1,782 1,783 1,784 1,785 1,786 1,787 1,788 1,789 1,790 1,791 1,792

less more

Notable events — 1780 AD

May 12 Charleston falls to British forces.
Jun 2 The Gordon Riots erupt in London.
Sep 23 Benedict Arnold's plot to surrender West Point is exposed.

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: Saturday
January 1, 1780
Ended on: Sunday
December 31, 1780
Friday the 13ths: 1
One Friday the 13th this year.
Easter Sunday: March 26
Sunday, March 26, 1780
Decade: 1780s
1780–1789
Century: 18th century
1701–1800
Millennium: 2nd millennium
1001–2000
Years ago: 246
246 years before 2026.

In other calendars

Hebrew: 5540 / 5541 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1193 / 1195 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Metal zodiac:Rat
Sexagenary cycle position 37 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 2323 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1158 / 1159 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1772 / 1773 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1702 / 1701 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 16
Digit product: 0
Digital root: 7
Palindrome: No
Bit width: 11 bits
Reversed: 871
Recamán's sequence: a(16,139) = 1,780
Square (n²): 3,168,400
Cube (n³): 5,639,752,000
Divisor count: 12
σ(n) — sum of divisors: 3,780
φ(n) — Euler's totient: 704
Sum of prime factors: 98

Primality

Prime factorization: 2 ² × 5 × 89

Nearest primes: 1,777 (−3) · 1,783 (+3)

Divisors & multiples

All divisors (12)

1 · 2 · 4 · 5 · 10 · 20 · 89 · 178 · 356 · 445 · 890 (half) · 1780

Aliquot sum (sum of proper divisors): 2,000

Factor pairs (a × b = 1,780)

1 × 1780

2 × 890

4 × 445

5 × 356

10 × 178

20 × 89

First multiples

1,780 · 3,560 (double) · 5,340 · 7,120 · 8,900 · 10,680 · 12,460 · 14,240 · 16,020 · 17,800

Sums & aliquot sequence

As a sum of two squares: 4² + 42² = 22² + 36²

As consecutive integers: 354 + 355 + 356 + 357 + 358 219 + 220 + … + 226 25 + 26 + … + 64

Aliquot sequence: 1,780 → 2,000 → 2,836 → 2,134 → 1,394 → 874 → 566 → 286 → 218 → 112 → 136 → 134 → 70 → 74 → 40 → 50 → 43 — unresolved within range

Continued fraction of √n

√1,780 = [42; (5, 3, 1, 4, 1, 1, 20, 1, 1, 4, 1, 3, 5, 84)]

Period length 14 — the block in parentheses repeats forever.

Representations

In words: one thousand seven hundred eighty
Ordinal: 1780th
Roman numeral: MDCCLXXX
Binary: 11011110100
Octal: 3364
Hexadecimal: 0x6F4
Base64: BvQ=
One's complement: 63,755 (16-bit)
Scientific notation: 1.78 × 10³
As a duration: 1,780 s = 29 minutes, 40 seconds

In other bases

ternary (3) 2102221

quaternary (4) 123310

quinary (5) 24110

senary (6) 12124

septenary (7) 5122

nonary (9) 2387

undecimal (11) 1379

duodecimal (12) 1044

tridecimal (13) a6c

tetradecimal (14) 912

pentadecimal (15) 7da

As an angle

1,780° = 4 × 360° + 340°

340° ≈ 5.934 rad

Compass bearing: NNW (north-northwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
Greek (Milesian): ͵αψπʹ
Mayan (base 20): 𝋤·𝋩·𝋠
Chinese: 一千七百八十
Chinese (financial): 壹仟柒佰捌拾

In other modern scripts

Eastern Arabic ١٧٨٠ Devanagari १७८० Bengali ১৭৮০ Tamil ௧௭௮௦ Thai ๑๗๘๐ Tibetan ༡༧༨༠ Khmer ១៧៨០ Lao ໑໗໘໐ Burmese ၁၇၈၀

Digit at this position in famous constants

π — Pi (π): Digit 1,780 = 8
e — Euler's number (e): Digit 1,780 = 2
φ — Golden ratio (φ): Digit 1,780 = 9
√2 — Pythagoras's (√2): Digit 1,780 = 4
ln 2 — Natural log of 2: Digit 1,780 = 5
γ — Euler-Mascheroni (γ): Digit 1,780 = 2

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1780, here are decompositions:

3 + 1777 = 1780
47 + 1733 = 1780
59 + 1721 = 1780
71 + 1709 = 1780
83 + 1697 = 1780
113 + 1667 = 1780
167 + 1613 = 1780
173 + 1607 = 1780

Showing the first eight; more decompositions exist.

Unicode codepoint

Extended Arabic-Indic Digit Four

U+06F4

Decimal digit (Nd)

UTF-8 encoding: DB B4 (2 bytes).

Lookup U+06F4 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0006F4

RGB(0, 6, 244)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.244.

Address: 0.0.6.244
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.6.244

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

Musical pitch

Heard as a frequency, 1,780 Hz is closest to:

Concert pitch (A4 = 440 Hz): A6 (1760 Hz, +20¢)
Scientific pitch (C4 = 256 Hz): A♯6 (1824.6 Hz, -43¢)
Baroque pitch (A4 = 415 Hz): A♯6 (1758.7 Hz, +21¢)

Position in π

The digit sequence 1780 first appears in π at position 15,510 of the decimal expansion (the 15,510ordinal-suffix:th 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 1780 on Pi Search ↗