number.wiki
Number

90

90 is a composite number, even, a calendar year.

Abundant Number Harshad / Niven Pronic / Oblong Year

Properties

Parity
Even
Digit count
2
Digit sum
9
Digital root
9
Palindrome
No
Divisor count
12
σ(n) — sum of divisors
234

Primality

Prime factorization: 2 × 3 2 × 5

Divisors & multiples

All divisors (12)
1 · 2 · 3 · 5 · 6 · 9 · 10 · 15 · 18 · 30 · 45 · 90
Aliquot sum (sum of proper divisors): 144
Factor pairs (a × b = 90)
1 × 90
2 × 45
3 × 30
5 × 18
6 × 15
9 × 10
First multiples
90 · 180 · 270 · 360 · 450 · 540 · 630 · 720 · 810 · 900

Representations

In words
ninety
Ordinal
90th
Roman numeral
XC
Binary
1011010
Octal
132
Hexadecimal
5A

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 90, here are decompositions:

  • 7 + 83 = 90
  • 11 + 79 = 90
  • 17 + 73 = 90
  • 19 + 71 = 90
  • 23 + 67 = 90
  • 29 + 61 = 90
  • 31 + 59 = 90
  • 37 + 53 = 90

Showing the first eight; more decompositions exist.

ASCII character

As an ASCII codepoint, 90 is Z. Printable ASCII character Z.

Hex color
#00005A
RGB(0, 0, 90)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.90.