number.wiki
Number

280

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

Abundant Number Happy Number Harshad / Niven Octagonal Year

Properties

Parity
Even
Digit count
3
Digit sum
10
Digital root
1
Palindrome
No
Divisor count
16
σ(n) — sum of divisors
720

Primality

Prime factorization: 2 3 × 5 × 7

Divisors & multiples

All divisors (16)
1 · 2 · 4 · 5 · 7 · 8 · 10 · 14 · 20 · 28 · 35 · 40 · 56 · 70 · 140 · 280
Aliquot sum (sum of proper divisors): 440
Factor pairs (a × b = 280)
1 × 280
2 × 140
4 × 70
5 × 56
7 × 40
8 × 35
10 × 28
14 × 20
First multiples
280 · 560 · 840 · 1,120 · 1,400 · 1,680 · 1,960 · 2,240 · 2,520 · 2,800

Representations

In words
two hundred eighty
Ordinal
280th
Roman numeral
CCLXXX
Binary
100011000
Octal
430
Hexadecimal
118

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 280, here are decompositions:

  • 3 + 277 = 280
  • 11 + 269 = 280
  • 17 + 263 = 280
  • 23 + 257 = 280
  • 29 + 251 = 280
  • 41 + 239 = 280
  • 47 + 233 = 280
  • 53 + 227 = 280

Showing the first eight; more decompositions exist.

Unicode codepoint
Ę
U+0118
Uppercase letter (Lu)

UTF-8 encoding: C4 98 (2 bytes).

Lookup U+0118 on Compart ↗ Lookup on FileFormat.Info ↗
Hex color
#000118
RGB(0, 1, 24)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.24.