Number

1,620

1,620 is a composite number, even, a calendar year.

1,620 (one thousand six hundred twenty) is an even 4-digit number. It is a composite number with 30 divisors, and factors as 2² × 3⁴ × 5. Its proper divisors sum to 3,462, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MDCXX and in binary, 11001010100.

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

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

1,608 1,609 1,610 1,611 1,612 1,613 1,614 1,615 1,616 1,617 1,618 1,619 1,620 1,621 1,622 1,623 1,624 1,625 1,626 1,627 1,628 1,629 1,630 1,631 1,632

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Notable events — 1620 AD

Nov 11 Pilgrims aboard the Mayflower sign the Mayflower Compact off Cape Cod.
Nov 8 The Battle of White Mountain crushes the Bohemian Protestant revolt.
Dec 21 The Mayflower's passengers come ashore at Plymouth.

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: Wednesday
January 1, 1620
Ended on: Thursday
December 31, 1620
Friday the 13ths: 2
2 Friday the 13ths this year.
Easter Sunday: April 19
Sunday, April 19, 1620
Decade: 1620s
1620–1629
Century: 17th century
1601–1700
Millennium: 2nd millennium
1001–2000
Years ago: 406
406 years before 2026.

In other calendars

Hebrew: 5380 / 5381 AM
Rosh Hashanah falls in September/October.
Islamic Hijri: 1029 / 1030 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: 2163 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
Persian Solar Hijri: 998 / 999 SH
Iranian calendar; Nowruz (new year) falls on the spring equinox.
Ethiopian: 1612 / 1613 ET
Year boundary at Enkutatash (September 11/12).
Indian National (Saka): 1542 / 1541 Saka
Indian national calendar; year starts in March.

Properties

Parity: Even
Digit count: 4
Digit sum: 9
Digit product: 0
Digital root: 9
Palindrome: No
Bit width: 11 bits
Reversed: 261
Recamán's sequence: a(712) = 1,620
Square (n²): 2,624,400
Cube (n³): 4,251,528,000
Divisor count: 30
σ(n) — sum of divisors: 5,082
φ(n) — Euler's totient: 432
Sum of prime factors: 21

Primality

Prime factorization: 2 ² × 3 ⁴ × 5

Nearest primes: 1,619 (−1) · 1,621 (+1)

Divisors & multiples

All divisors (30)

1 · 2 · 3 · 4 · 5 · 6 · 9 · 10 · 12 · 15 · 18 · 20 · 27 · 30 · 36 · 45 · 54 · 60 · 81 · 90 · 108 · 135 · 162 · 180 · 270 · 324 · 405 · 540 · 810 (half) · 1620

Aliquot sum (sum of proper divisors): 3,462

Factor pairs (a × b = 1,620)

1 × 1620

2 × 810

3 × 540

4 × 405

5 × 324

6 × 270

9 × 180

10 × 162

12 × 135

15 × 108

18 × 90

20 × 81

27 × 60

30 × 54

36 × 45

First multiples

1,620 · 3,240 (double) · 4,860 · 6,480 · 8,100 · 9,720 · 11,340 · 12,960 · 14,580 · 16,200

Sums & aliquot sequence

As a sum of two squares: 18² + 36²

As consecutive integers: 539 + 540 + 541 322 + 323 + 324 + 325 + 326 199 + 200 + … + 206 176 + 177 + … + 184

Aliquot sequence: 1,620 → 3,462 → 3,474 → 4,092 → 6,660 → 14,088 → 21,192 → 31,848 → 47,832 → 71,808 → 148,512 → 359,520 → 946,848 → 1,895,712 → 4,539,360 → 12,180,336 → 23,781,648 — unresolved within range

Continued fraction of √n

√1,620 = [40; (4, 80)]

Period length 2 — the block in parentheses repeats forever.

Representations

In words: one thousand six hundred twenty
Ordinal: 1620th
Roman numeral: MDCXX
Binary: 11001010100
Octal: 3124
Hexadecimal: 0x654
Base64: BlQ=
One's complement: 63,915 (16-bit)
Scientific notation: 1.62 × 10³
As a duration: 1,620 s = 27 minutes

In other bases

ternary (3) 2020000

quaternary (4) 121110

quinary (5) 22440

senary (6) 11300

septenary (7) 4503

nonary (9) 2200

undecimal (11) 1243

duodecimal (12) b30

tridecimal (13) 978

tetradecimal (14) 83a

pentadecimal (15) 730

As an angle

1,620° = 4 × 360° + 180°

180° ≈ 3.142 rad

Compass bearing: S (south)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 ·
Egyptian hieroglyphic: 𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
Greek (Milesian): ͵αχκʹ
Mayan (base 20): 𝋤·𝋡·𝋠
Chinese: 一千六百二十
Chinese (financial): 壹仟陸佰貳拾

In other modern scripts

Eastern Arabic ١٦٢٠ Devanagari १६२० Bengali ১৬২০ Tamil ௧௬௨௦ Thai ๑๖๒๐ Tibetan ༡༦༢༠ Khmer ១៦២០ Lao ໑໖໒໐ Burmese ၁၆၂၀

Digit at this position in famous constants

π — Pi (π): Digit 1,620 = 9
e — Euler's number (e): Digit 1,620 = 7
φ — Golden ratio (φ): Digit 1,620 = 7
√2 — Pythagoras's (√2): Digit 1,620 = 8
ln 2 — Natural log of 2: Digit 1,620 = 6
γ — Euler-Mascheroni (γ): Digit 1,620 = 9

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 1620, here are decompositions:

7 + 1613 = 1620
11 + 1609 = 1620
13 + 1607 = 1620
19 + 1601 = 1620
23 + 1597 = 1620
37 + 1583 = 1620
41 + 1579 = 1620
53 + 1567 = 1620

Showing the first eight; more decompositions exist.

Unicode codepoint

Arabic Hamza Above

U+0654

Non-spacing mark (Mn)

UTF-8 encoding: D9 94 (2 bytes).

Lookup U+0654 on Compart ↗ Lookup on FileFormat.Info ↗

Hex color

#000654

RGB(0, 6, 84)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.6.84.

Address: 0.0.6.84
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.6.84

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

Musical pitch

Heard as a frequency, 1,620 Hz is closest to:

Concert pitch (A4 = 440 Hz): G♯6 (1661.2 Hz, -43¢)
Scientific pitch (C4 = 256 Hz): G♯6 (1625.5 Hz, -6¢)
Baroque pitch (A4 = 415 Hz): A6 (1660 Hz, -42¢)

Position in π

The digit sequence 1620 first appears in π at position 1,324 of the decimal expansion (the 1,324ordinal-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 1620 on Pi Search ↗