Number

780

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

Abundant Number Arithmetic Number Evil Number Harshad / Niven Hexagonal Practical Number Recamán's Sequence Semiperfect Number Triangular Year

Historical context — 780 AD

Calendar year

Year 780 (DCCLXXX) was a leap year starting on Saturday of the Julian calendar, the 780th year of the Common Era (CE) and Anno Domini (AD) designations, the 780th year of the 1st millennium, the 80th year of the 8th century, and the 1st year of the 780s decade.

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Historical context — 780 BC

Decade

This article concerns the period 789 BC – 780 BC.

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

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: Tuesday
January 1, 780
Ended on: Wednesday
December 31, 780
Friday the 13ths: 1
One Friday the 13th this year.
Decade: 780s
780–789
Century: 8th century
701–800
Millennium: 1st millennium
1–1000
Years ago: 1,246
1246 years before 2026.

In other calendars

Hebrew: 4540 / 4541 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 163 / 164 AH
Lunar calendar; year spans differ from Gregorian.
Chinese: Year of the zodiac:Metal zodiac:Monkey
Sexagenary cycle position 57 of 60. Lunar new year falls in late January / mid-February.
Buddhist Era: 1323 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 158 / 159 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 772 / 773 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 702 / 701 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 3
Digit sum: 15
Digit product: 0
Digital root: 6
Palindrome: No
Bit width: 10 bits
Reversed: 87
Recamán's sequence: a(871) = 780
Square (n²): 608,400
Cube (n³): 474,552,000
Divisor count: 24
σ(n) — sum of divisors: 2,352
φ(n) — Euler's totient: 192
Sum of prime factors: 25

Primality

Prime factorization: 2 ² × 3 × 5 × 13

Nearest primes: 773 (−7) · 787 (+7)

Divisors & multiples

All divisors (24)

1 · 2 · 3 · 4 · 5 · 6 · 10 · 12 · 13 · 15 · 20 · 26 · 30 · 39 · 52 · 60 · 65 · 78 · 130 · 156 · 195 · 260 · 390 (half) · 780

Aliquot sum (sum of proper divisors): 1,572

Factor pairs (a × b = 780)

1 × 780

2 × 390

3 × 260

4 × 195

5 × 156

6 × 130

10 × 78

12 × 65

13 × 60

15 × 52

20 × 39

26 × 30

First multiples

780 · 1,560 (double) · 2,340 · 3,120 · 3,900 · 4,680 · 5,460 · 6,240 · 7,020 · 7,800

Sums & aliquot sequence

As consecutive integers: 259 + 260 + 261 154 + 155 + 156 + 157 + 158 94 + 95 + … + 101 54 + 55 + … + 66

Aliquot sequence: 780 → 1,572 → 2,124 → 3,336 → 5,064 → 7,656 → 13,944 → 26,376 → 49,464 → 88,536 → 187,944 → 295,896 → 443,904 → 812,340 → 1,652,304 → 2,767,056 → 4,803,888 — unresolved within range

Representations

In words: seven hundred eighty
Ordinal: 780th
Roman numeral: DCCLXXX
Binary: 1100001100
Octal: 1414
Hexadecimal: 0x30C
Base64: Aww=
One's complement: 64,755 (16-bit)

In other bases

ternary (3) 1001220

quaternary (4) 30030

quinary (5) 11110

senary (6) 3340

septenary (7) 2163

nonary (9) 1056

undecimal (11) 64a

duodecimal (12) 550

tridecimal (13) 480

tetradecimal (14) 3da

pentadecimal (15) 370

Historical numeral systems

Babylonian (base 60): 𒌋𒁹𒁹𒁹 ·
Egyptian hieroglyphic: 𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆𓎆𓎆
Greek (Milesian): ψπʹ
Mayan (base 20): 𝋡·𝋳·𝋠
Chinese: 七百八十
Chinese (financial): 柒佰捌拾

In other modern scripts

Eastern Arabic ٧٨٠ Devanagari ७८० Bengali ৭৮০ Tamil ௭௮௦ Thai ๗๘๐ Tibetan ༧༨༠ Khmer ៧៨០ Lao ໗໘໐ Burmese ၇၈၀

Digit at this position in famous constants

π — Pi (π): Digit 780 = 5
e — Euler's number (e): Digit 780 = 1
φ — Golden ratio (φ): Digit 780 = 0
√2 — Pythagoras's (√2): Digit 780 = 4
ln 2 — Natural log of 2: Digit 780 = 6
γ — Euler-Mascheroni (γ): Digit 780 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 780, here are decompositions:

7 + 773 = 780
11 + 769 = 780
19 + 761 = 780
23 + 757 = 780
29 + 751 = 780
37 + 743 = 780
41 + 739 = 780
47 + 733 = 780

Showing the first eight; more decompositions exist.

Unicode codepoint

Combining Caron

U+030C

Non-spacing mark (Mn)

UTF-8 encoding: CC 8C (2 bytes).

Lookup U+030C on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00030C

RGB(0, 3, 12)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.3.12.

Address: 0.0.3.12
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.3.12

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

NANP area code 780

The number 780 is an active NANP area code (North American Numbering Plan).

Primary area: Edmonton / Northern Alberta
Region: Alberta
Country: Canada

Most NANP area codes have multiple overlays in dense regions; the primary area listed is the historic/largest population center for this code.

Look up area code 780 ↗