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20,820

20,820 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.).
Abundant Number Arithmetic Number Evil Number Gapful Number Harshad / Niven Recamán's Sequence Semiperfect Number

Properties

Parity
Even
Digit count
5
Digit sum
12
Digit product
0
Digital root
3
Palindrome
No
Bit width
15 bits
Reversed
2,802
Recamán's sequence
a(42,199) = 20,820
Square (n²)
433,472,400
Cube (n³)
9,024,895,368,000
Divisor count
24
σ(n) — sum of divisors
58,464
φ(n) — Euler's totient
5,536
Sum of prime factors
359

Primality

Prime factorization: 2 2 × 3 × 5 × 347

Nearest primes: 20,809 (−11) · 20,849 (+29)

Divisors & multiples

All divisors (24)
1 · 2 · 3 · 4 · 5 · 6 · 10 · 12 · 15 · 20 · 30 · 60 · 347 · 694 · 1041 · 1388 · 1735 · 2082 · 3470 · 4164 · 5205 · 6940 · 10410 (half) · 20820
Aliquot sum (sum of proper divisors): 37,644
Factor pairs (a × b = 20,820)
1 × 20820
2 × 10410
3 × 6940
4 × 5205
5 × 4164
6 × 3470
10 × 2082
12 × 1735
15 × 1388
20 × 1041
30 × 694
60 × 347
First multiples
20,820 · 41,640 (double) · 62,460 · 83,280 · 104,100 · 124,920 · 145,740 · 166,560 · 187,380 · 208,200

Sums & aliquot sequence

As consecutive integers: 6,939 + 6,940 + 6,941 4,162 + 4,163 + 4,164 + 4,165 + 4,166 2,599 + 2,600 + … + 2,606 1,381 + 1,382 + … + 1,395
Aliquot sequence: 20,820 37,644 50,220 112,404 189,996 261,588 348,812 309,748 236,364 315,180 706,932 1,111,248 1,999,106 999,556 757,836 1,224,144 2,202,162 — unresolved within range

Representations

In words
twenty thousand eight hundred twenty
Ordinal
20820th
Binary
101000101010100
Octal
50524
Hexadecimal
0x5154
Base64
UVQ=
One's complement
44,715 (16-bit)
In other bases
ternary (3) 1001120010
quaternary (4) 11011110
quinary (5) 1131240
senary (6) 240220
septenary (7) 114462
nonary (9) 31503
undecimal (11) 14708
duodecimal (12) 10070
tridecimal (13) 9627
tetradecimal (14) 7832
pentadecimal (15) 6280

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹 𒌋𒌋𒌋𒌋𒁹𒁹𒁹𒁹𒁹𒁹𒁹 ·
Egyptian hieroglyphic
𓂍𓂍𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
Greek (Milesian)
͵κωκʹ
Mayan (base 20)
𝋢·𝋬·𝋡·𝋠
Chinese
二萬零八百二十
Chinese (financial)
貳萬零捌佰貳拾
In other modern scripts
Eastern Arabic ٢٠٨٢٠ Devanagari २०८२० Bengali ২০৮২০ Tamil ௨௦௮௨௦ Thai ๒๐๘๒๐ Tibetan ༢༠༨༢༠ Khmer ២០៨២០ Lao ໒໐໘໒໐ Burmese ၂၀၈၂၀

Digit at this position in famous constants

π — Pi (π)
Digit 20,820 = 0
e — Euler's number (e)
Digit 20,820 = 4
φ — Golden ratio (φ)
Digit 20,820 = 2
√2 — Pythagoras's (√2)
Digit 20,820 = 5
ln 2 — Natural log of 2
Digit 20,820 = 9
γ — Euler-Mascheroni (γ)
Digit 20,820 = 6

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 20820, here are decompositions:

  • 11 + 20809 = 20820
  • 13 + 20807 = 20820
  • 31 + 20789 = 20820
  • 47 + 20773 = 20820
  • 61 + 20759 = 20820
  • 67 + 20753 = 20820
  • 71 + 20749 = 20820
  • 73 + 20747 = 20820

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5154
U+5154
Other letter (Lo)

UTF-8 encoding: E5 85 94 (3 bytes).

Hex color
#005154
RGB(0, 81, 84)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.81.84.

Address
0.0.81.84
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.81.84

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

Position in π

The digit sequence 20820 first appears in π at position 31,451 of the decimal expansion (the 31,451ordinal-suffix:st 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.