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20,990

20,990 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.).
Deficient Number Sphenic Number Squarefree

Properties

Parity
Even
Digit count
5
Digit sum
20
Digital root
2
Palindrome
No
Divisor count
8
σ(n) — sum of divisors
37,800

Primality

Prime factorization: 2 × 5 × 2099

Divisors & multiples

All divisors (8)
1 · 2 · 5 · 10 · 2099 · 4198 · 10495 · 20990
Aliquot sum (sum of proper divisors): 16,810
Factor pairs (a × b = 20,990)
1 × 20990
2 × 10495
5 × 4198
10 × 2099
First multiples
20,990 · 41,980 · 62,970 · 83,960 · 104,950 · 125,940 · 146,930 · 167,920 · 188,910 · 209,900

Representations

In words
twenty thousand nine hundred ninety
Ordinal
20990th
Binary
101000111111110
Octal
50776
Hexadecimal
51FE

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 20990, here are decompositions:

  • 7 + 20983 = 20990
  • 31 + 20959 = 20990
  • 43 + 20947 = 20990
  • 61 + 20929 = 20990
  • 103 + 20887 = 20990
  • 181 + 20809 = 20990
  • 241 + 20749 = 20990
  • 271 + 20719 = 20990

Showing the first eight; more decompositions exist.

Unicode codepoint
CJK Unified Ideograph-51Fe
U+51FE
Other letter (Lo)

UTF-8 encoding: E5 87 BE (3 bytes).

Hex color
#0051FE
RGB(0, 81, 254)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.81.254.