Number

1,720

1,720 is a composite number, even, a calendar year.

1,720 (one thousand seven hundred twenty) is an even 4-digit number. It is a composite number with 16 divisors, and factors as 2³ × 5 × 43. Its proper divisors sum to 2,240, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCCXX and in binary, 11010111000.

Abundant Number Evil Number Gapful Number Harshad / Niven Practical Number Recamán's Sequence Semiperfect Number Year

Interestingness

★ ★ ★ ☆ ☆

5 notable facts · grade C

1,708 1,709 1,710 1,711 1,712 1,713 1,714 1,715 1,716 1,717 1,718 1,719 1,720 1,721 1,722 1,723 1,724 1,725 1,726 1,727 1,728 1,729 1,730 1,731 1,732

less more

Notable events — 1720 AD

Aug 24 The South Sea Bubble bursts in London.
Sep 30 Philadelphia's Quaker Meeting passes anti-slavery petitions.
Jun 23 Plague returns to Marseille in its last great outbreak in western Europe.

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, 1720
Ended on: Tuesday
December 31, 1720
Friday the 13ths: 2
2 Friday the 13ths this year.
Easter Sunday: March 31
Sunday, March 31, 1720
Decade: 1720s
1720–1729
Century: 18th century
1701–1800
Millennium: 2nd millennium
1001–2000
Years ago: 306
306 years before 2026.

In other calendars

Hebrew: 5480 / 5481 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1132 / 1133 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: 2263 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1098 / 1099 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1712 / 1713 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1642 / 1641 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 10
Digit product: 0
Digital root: 1
Palindrome: No
Bit width: 11 bits
Reversed: 271
Recamán's sequence: a(1,180) = 1,720
Square (n²): 2,958,400
Cube (n³): 5,088,448,000
Divisor count: 16
σ(n) — sum of divisors: 3,960
φ(n) — Euler's totient: 672
Sum of prime factors: 54

Primality

Prime factorization: 2 ³ × 5 × 43

Nearest primes: 1,709 (−11) · 1,721 (+1)

Divisors & multiples

All divisors (16)

1 · 2 · 4 · 5 · 8 · 10 · 20 · 40 · 43 · 86 · 172 · 215 · 344 · 430 · 860 (half) · 1720

Aliquot sum (sum of proper divisors): 2,240

Factor pairs (a × b = 1,720)

1 × 1720

2 × 860

4 × 430

5 × 344

8 × 215

10 × 172

20 × 86

40 × 43

First multiples

1,720 · 3,440 (double) · 5,160 · 6,880 · 8,600 · 10,320 · 12,040 · 13,760 · 15,480 · 17,200

Sums & aliquot sequence

As consecutive integers: 342 + 343 + 344 + 345 + 346 100 + 101 + … + 115 19 + 20 + … + 61

Aliquot sequence: 1,720 → 2,240 → 3,856 → 3,646 → 1,826 → 1,198 → 602 → 454 → 230 → 202 → 104 → 106 → 56 → 64 → 63 → 41 → 1 — unresolved within range

Continued fraction of √n

√1,720 = [41; (2, 8, 1, 2, 1, 1, 3, 1, 1, 2, 1, 8, 2, 82)]

Period length 14 — the block in parentheses repeats forever.

Representations

In words: one thousand seven hundred twenty
Ordinal: 1720th
Roman numeral: MDCCXX
Binary: 11010111000
Octal: 3270
Hexadecimal: 0x6B8
Base64: Brg=
One's complement: 63,815 (16-bit)
Scientific notation: 1.72 × 10³
As a duration: 1,720 s = 28 minutes, 40 seconds

In other bases

ternary (3) 2100201

quaternary (4) 122320

quinary (5) 23340

senary (6) 11544

septenary (7) 5005

nonary (9) 2321

undecimal (11) 1324

duodecimal (12) bb4

tridecimal (13) a24

tetradecimal (14) 8ac

pentadecimal (15) 79a

Palindromic in base 7

As an angle

1,720° = 4 × 360° + 280°

280° ≈ 4.887 rad

Compass bearing: W (west)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
Greek (Milesian): ͵αψκʹ
Mayan (base 20): 𝋤·𝋦·𝋠
Chinese: 一千七百二十
Chinese (financial): 壹仟柒佰貳拾

In other modern scripts

Eastern Arabic ١٧٢٠ Devanagari १७२० Bengali ১৭২০ Tamil ௧௭௨௦ Thai ๑๗๒๐ Tibetan ༡༧༢༠ Khmer ១៧២០ Lao ໑໗໒໐ Burmese ၁၇၂၀

Digit at this position in famous constants

π — Pi (π): Digit 1,720 = 3
e — Euler's number (e): Digit 1,720 = 1
φ — Golden ratio (φ): Digit 1,720 = 8
√2 — Pythagoras's (√2): Digit 1,720 = 4
ln 2 — Natural log of 2: Digit 1,720 = 6
γ — Euler-Mascheroni (γ): Digit 1,720 = 9

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1720, here are decompositions:

11 + 1709 = 1720
23 + 1697 = 1720
53 + 1667 = 1720
83 + 1637 = 1720
101 + 1619 = 1720
107 + 1613 = 1720
113 + 1607 = 1720
137 + 1583 = 1720

Showing the first eight; more decompositions exist.

Unicode codepoint

Arabic Letter Lam With Three Dots Below

U+06B8

Other letter (Lo)

UTF-8 encoding: DA B8 (2 bytes).

Lookup U+06B8 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#0006B8

RGB(0, 6, 184)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.184.

Address: 0.0.6.184
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.6.184

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

Musical pitch

Heard as a frequency, 1,720 Hz is closest to:

Concert pitch (A4 = 440 Hz): A6 (1760 Hz, -40¢)
Scientific pitch (C4 = 256 Hz): A6 (1722.2 Hz, -2¢)
Baroque pitch (A4 = 415 Hz): A♯6 (1758.7 Hz, -39¢)

Position in π

The digit sequence 1720 first appears in π at position 48,343 of the decimal expansion (the 48,343ordinal-suffix:rd 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 1720 on Pi Search ↗