Number

1,660

1,660 is a composite number, even, a calendar year.

1,660 (one thousand six hundred sixty) is an even 4-digit number. It is a composite number with 12 divisors, and factors as 2² × 5 × 83. Its proper divisors sum to 1,868, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCLX and in binary, 11001111100.

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

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

1,648 1,649 1,650 1,651 1,652 1,653 1,654 1,655 1,656 1,657 1,658 1,659 1,660 1,661 1,662 1,663 1,664 1,665 1,666 1,667 1,668 1,669 1,670 1,671 1,672

less more

Notable events — 1660 AD

May 29 Charles II is restored to the English throne.
Jan 1 Samuel Pepys begins his diary.
Oct 13 The Royal Society is granted its charter (formally chartered 1662).

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: 53
Long year: contains 53 ISO weeks.
Started on: Thursday
January 1, 1660
Ended on: Friday
December 31, 1660
Friday the 13ths: 2
2 Friday the 13ths this year.
Easter Sunday: March 28
Sunday, March 28, 1660
Decade: 1660s
1660–1669
Century: 17th century
1601–1700
Millennium: 2nd millennium
1001–2000
Years ago: 366
366 years before 2026.

In other calendars

Hebrew: 5420 / 5421 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1070 / 1071 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: 2203 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 1038 / 1039 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1652 / 1653 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1582 / 1581 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 13
Digit product: 0
Digital root: 4
Palindrome: No
Bit width: 11 bits
Reversed: 661
Flips to (rotate 180°): 991
Recamán's sequence: a(788) = 1,660
Square (n²): 2,755,600
Cube (n³): 4,574,296,000
Divisor count: 12
σ(n) — sum of divisors: 3,528
φ(n) — Euler's totient: 656
Sum of prime factors: 92

Primality

Prime factorization: 2 ² × 5 × 83

Nearest primes: 1,657 (−3) · 1,663 (+3)

Divisors & multiples

All divisors (12)

1 · 2 · 4 · 5 · 10 · 20 · 83 · 166 · 332 · 415 · 830 (half) · 1660

Aliquot sum (sum of proper divisors): 1,868

Factor pairs (a × b = 1,660)

1 × 1660

2 × 830

4 × 415

5 × 332

10 × 166

20 × 83

First multiples

1,660 · 3,320 (double) · 4,980 · 6,640 · 8,300 · 9,960 · 11,620 · 13,280 · 14,940 · 16,600

Sums & aliquot sequence

As consecutive integers: 330 + 331 + 332 + 333 + 334 204 + 205 + … + 211 22 + 23 + … + 61

Aliquot sequence: 1,660 → 1,868 → 1,408 → 1,652 → 1,708 → 1,764 → 3,423 → 1,825 → 469 → 75 → 49 → 8 → 7 → 1 → 0 — terminates at zero

Continued fraction of √n

√1,660 = [40; (1, 2, 1, 8, 3, 3, 1, 1, 3, 1, 2, 1, 1, 1, 1, 2, 5, 20, 5, 2, 1, 1, 1, 1, …)]

Period length 36 — the block in parentheses repeats forever.

Representations

In words: one thousand six hundred sixty
Ordinal: 1660th
Roman numeral: MDCLX
Binary: 11001111100
Octal: 3174
Hexadecimal: 0x67C
Base64: Bnw=
One's complement: 63,875 (16-bit)
Scientific notation: 1.66 × 10³
As a duration: 1,660 s = 27 minutes, 40 seconds

In other bases

ternary (3) 2021111

quaternary (4) 121330

quinary (5) 23120

senary (6) 11404

septenary (7) 4561

nonary (9) 2244

undecimal (11) 127a

duodecimal (12) b64

tridecimal (13) 9a9

tetradecimal (14) 868

pentadecimal (15) 75a

Palindromic in base 13, base 14

As an angle

1,660° = 4 × 360° + 220°

220° ≈ 3.84 rad

Compass bearing: SW (southwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆𓎆𓎆𓎆𓎆
Greek (Milesian): ͵αχξʹ
Mayan (base 20): 𝋤·𝋣·𝋠
Chinese: 一千六百六十
Chinese (financial): 壹仟陸佰陸拾

In other modern scripts

Eastern Arabic ١٦٦٠ Devanagari १६६० Bengali ১৬৬০ Tamil ௧௬௬௦ Thai ๑๖๖๐ Tibetan ༡༦༦༠ Khmer ១៦៦០ Lao ໑໖໖໐ Burmese ၁၆၆၀

Digit at this position in famous constants

π — Pi (π): Digit 1,660 = 7
e — Euler's number (e): Digit 1,660 = 4
φ — Golden ratio (φ): Digit 1,660 = 4
√2 — Pythagoras's (√2): Digit 1,660 = 4
ln 2 — Natural log of 2: Digit 1,660 = 6
γ — Euler-Mascheroni (γ): Digit 1,660 = 7

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1660, here are decompositions:

3 + 1657 = 1660
23 + 1637 = 1660
41 + 1619 = 1660
47 + 1613 = 1660
53 + 1607 = 1660
59 + 1601 = 1660
89 + 1571 = 1660
101 + 1559 = 1660

Showing the first eight; more decompositions exist.

Unicode codepoint

Arabic Letter Teh With Ring

U+067C

Other letter (Lo)

UTF-8 encoding: D9 BC (2 bytes).

Lookup U+067C on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#00067C

RGB(0, 6, 124)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.124.

Address: 0.0.6.124
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.6.124

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

Musical pitch

Heard as a frequency, 1,660 Hz is closest to:

Concert pitch (A4 = 440 Hz): G♯6 (1661.2 Hz, -1¢)
Scientific pitch (C4 = 256 Hz): G♯6 (1625.5 Hz, +36¢)
Baroque pitch (A4 = 415 Hz): A6 (1660 Hz, exact)

Position in π

The digit sequence 1660 first appears in π at position 3,994 of the decimal expansion (the 3,994ordinal-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 1660 on Pi Search ↗