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21,620

21,620 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 Gapful Number Odious Number Pernicious Number Practical Number Recamán's Sequence Semiperfect Number

Properties

Parity
Even
Digit count
5
Digit sum
11
Digit product
0
Digital root
2
Palindrome
No
Bit width
15 bits
Reversed
2,612
Recamán's sequence
a(40,599) = 21,620
Square (n²)
467,424,400
Cube (n³)
10,105,715,528,000
Divisor count
24
σ(n) — sum of divisors
48,384
φ(n) — Euler's totient
8,096
Sum of prime factors
79

Primality

Prime factorization: 2 2 × 5 × 23 × 47

Nearest primes: 21,617 (−3) · 21,647 (+27)

Divisors & multiples

All divisors (24)
1 · 2 · 4 · 5 · 10 · 20 · 23 · 46 · 47 · 92 · 94 · 115 · 188 · 230 · 235 · 460 · 470 · 940 · 1081 · 2162 · 4324 · 5405 · 10810 (half) · 21620
Aliquot sum (sum of proper divisors): 26,764
Factor pairs (a × b = 21,620)
1 × 21620
2 × 10810
4 × 5405
5 × 4324
10 × 2162
20 × 1081
23 × 940
46 × 470
47 × 460
92 × 235
94 × 230
115 × 188
First multiples
21,620 · 43,240 (double) · 64,860 · 86,480 · 108,100 · 129,720 · 151,340 · 172,960 · 194,580 · 216,200

Sums & aliquot sequence

As consecutive integers: 4,322 + 4,323 + 4,324 + 4,325 + 4,326 2,699 + 2,700 + … + 2,706 929 + 930 + … + 951 521 + 522 + … + 560
Aliquot sequence: 21,620 26,764 20,080 26,792 26,668 21,212 15,916 13,316 9,994 5,846 3,274 1,640 2,140 2,396 1,804 1,724 1,300 — unresolved within range

Representations

In words
twenty-one thousand six hundred twenty
Ordinal
21620th
Binary
101010001110100
Octal
52164
Hexadecimal
0x5474
Base64
VHQ=
One's complement
43,915 (16-bit)
In other bases
ternary (3) 1002122202
quaternary (4) 11101310
quinary (5) 1142440
senary (6) 244032
septenary (7) 120014
nonary (9) 32582
undecimal (11) 15275
duodecimal (12) 10618
tridecimal (13) 9ac1
tetradecimal (14) 7c44
pentadecimal (15) 6615

Historical numeral systems

Babylonian (base 60)
𒁹𒁹𒁹𒁹𒁹𒁹 · 𒌋𒌋
Egyptian hieroglyphic
𓂍𓂍𓆼𓍢𓍢𓍢𓍢𓍢𓍢𓎆𓎆
Greek (Milesian)
͵καχκʹ
Mayan (base 20)
𝋢·𝋮·𝋡·𝋠
Chinese
二萬一千六百二十
Chinese (financial)
貳萬壹仟陸佰貳拾
In other modern scripts
Eastern Arabic ٢١٦٢٠ Devanagari २१६२० Bengali ২১৬২০ Tamil ௨௧௬௨௦ Thai ๒๑๖๒๐ Tibetan ༢༡༦༢༠ Khmer ២១៦២០ Lao ໒໑໖໒໐ Burmese ၂၁၆၂၀

Digit at this position in famous constants

π — Pi (π)
Digit 21,620 = 3
e — Euler's number (e)
Digit 21,620 = 7
φ — Golden ratio (φ)
Digit 21,620 = 5
√2 — Pythagoras's (√2)
Digit 21,620 = 6
ln 2 — Natural log of 2
Digit 21,620 = 0
γ — Euler-Mascheroni (γ)
Digit 21,620 = 3

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 21620, here are decompositions:

  • 3 + 21617 = 21620
  • 7 + 21613 = 21620
  • 19 + 21601 = 21620
  • 31 + 21589 = 21620
  • 43 + 21577 = 21620
  • 61 + 21559 = 21620
  • 97 + 21523 = 21620
  • 103 + 21517 = 21620

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-5474
U+5474
Other letter (Lo)

UTF-8 encoding: E5 91 B4 (3 bytes).

Hex color
#005474
RGB(0, 84, 116)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.84.116.

Address
0.0.84.116
Class
reserved
IPv4-mapped IPv6
::ffff:0.0.84.116

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

Position in π

The digit sequence 21620 first appears in π at position 1,323 of the decimal expansion (the 1,323ordinal-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.