Live analysis

2,820

2,820 is a composite number, even.

This number doesn't have a permanent NumberWiki page yet — what you see below is computed live. Pages get added to the permanent index when they're notable (years, primes, curated, etc.).

2,820 (two thousand eight hundred twenty) is an even 4-digit number. It is a composite number with 24 divisors, and factors as 2² × 3 × 5 × 47. Its proper divisors sum to 5,244, more than the number itself, making it an abundant number. Written other ways, in Roman numerals it is MMDCCCXX and in binary, 101100000100.

Abundant Number Arithmetic Number Cube-Free Evil Number Gapful Number Harshad / Niven Practical Number Recamán's Sequence Semiperfect Number

Interestingness

★ ★ ★ ★ ☆

7 notable facts · grade B

2,808 2,809 2,810 2,811 2,812 2,813 2,814 2,815 2,816 2,817 2,818 2,819 2,820 2,821 2,822 2,823 2,824 2,825 2,826 2,827 2,828 2,829 2,830 2,831 2,832

less more

Properties

Parity: Even
Digit count: 4
Digit sum: 12
Digit product: 0
Digital root: 3
Palindrome: No
Bit width: 12 bits
Reversed: 282
Recamán's sequence: a(2,567) = 2,820
Square (n²): 7,952,400
Cube (n³): 22,425,768,000
Divisor count: 24
σ(n) — sum of divisors: 8,064
φ(n) — Euler's totient: 736
Sum of prime factors: 59

Primality

Prime factorization: 2 ² × 3 × 5 × 47

Nearest primes: 2,819 (−1) · 2,833 (+13)

Divisors & multiples

All divisors (24)

1 · 2 · 3 · 4 · 5 · 6 · 10 · 12 · 15 · 20 · 30 · 47 · 60 · 94 · 141 · 188 · 235 · 282 · 470 · 564 · 705 · 940 · 1410 (half) · 2820

Aliquot sum (sum of proper divisors): 5,244

Factor pairs (a × b = 2,820)

1 × 2820

2 × 1410

3 × 940

4 × 705

5 × 564

6 × 470

10 × 282

12 × 235

15 × 188

20 × 141

30 × 94

47 × 60

First multiples

2,820 · 5,640 (double) · 8,460 · 11,280 · 14,100 · 16,920 · 19,740 · 22,560 · 25,380 · 28,200

Sums & aliquot sequence

As consecutive integers: 939 + 940 + 941 562 + 563 + 564 + 565 + 566 349 + 350 + … + 356 181 + 182 + … + 195

Aliquot sequence: 2,820 → 5,244 → 8,196 → 10,956 → 17,268 → 23,052 → 34,404 → 48,924 → 79,820 → 101,284 → 75,970 → 63,998 → 40,762 → 21,338 → 11,494 → 8,234 → 4,726 — unresolved within range

Continued fraction of √n

√2,820 = [53; (9, 1, 1, 1, 4, 1, 1, 1, 9, 106)]

Period length 10 — the block in parentheses repeats forever.

Representations

In words: two thousand eight hundred twenty
Ordinal: 2820th
Roman numeral: MMDCCCXX
Binary: 101100000100
Octal: 5404
Hexadecimal: 0xB04
Base64: CwQ=
One's complement: 62,715 (16-bit)
Scientific notation: 2.82 × 10³
As a duration: 2,820 s = 47 minutes

In other bases

ternary (3) 10212110

quaternary (4) 230010

quinary (5) 42240

senary (6) 21020

septenary (7) 11136

nonary (9) 3773

undecimal (11) 2134

duodecimal (12) 1770

tridecimal (13) 138c

tetradecimal (14) 1056

pentadecimal (15) c80

Palindromic in base 9

As an angle

2,820° = 7 × 360° + 300°

300° ≈ 5.236 rad

Compass bearing: WNW (west-northwest)

Why does a circle have 360 degrees? →

Historical numeral systems

Babylonian (base 60): 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 ·
Egyptian hieroglyphic: 𓆼𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
Greek (Milesian): ͵βωκʹ
Mayan (base 20): 𝋧·𝋡·𝋠
Chinese: 二千八百二十
Chinese (financial): 貳仟捌佰貳拾

In other modern scripts

Eastern Arabic ٢٨٢٠ Devanagari २८२० Bengali ২৮২০ Tamil ௨௮௨௦ Thai ๒๘๒๐ Tibetan ༢༨༢༠ Khmer ២៨២០ Lao ໒໘໒໐ Burmese ၂၈၂၀

Digit at this position in famous constants

π — Pi (π): Digit 2,820 = 6
e — Euler's number (e): Digit 2,820 = 4
φ — Golden ratio (φ): Digit 2,820 = 5
√2 — Pythagoras's (√2): Digit 2,820 = 0
ln 2 — Natural log of 2: Digit 2,820 = 4
γ — Euler-Mascheroni (γ): Digit 2,820 = 5

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 2820, here are decompositions:

17 + 2803 = 2820
19 + 2801 = 2820
23 + 2797 = 2820
29 + 2791 = 2820
31 + 2789 = 2820
43 + 2777 = 2820
53 + 2767 = 2820
67 + 2753 = 2820

Showing the first eight; more decompositions exist.

Hex color

#000B04

RGB(0, 11, 4)

IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.11.4.

Address: 0.0.11.4
Class: reserved
IPv4-mapped IPv6: ::ffff:0.0.11.4

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

Musical pitch

Heard as a frequency, 2,820 Hz is closest to:

Concert pitch (A4 = 440 Hz): F7 (2793.8 Hz, +16¢)
Scientific pitch (C4 = 256 Hz): F♯7 (2896.3 Hz, -46¢ — about midway to F7)
Baroque pitch (A4 = 415 Hz): F♯7 (2791.8 Hz, +17¢)

Position in π

The digit sequence 2820 first appears in π at position 19,769 of the decimal expansion (the 19,769ordinal-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 2820 on Pi Search ↗