number.wiki
Number

400

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

Abundant Number Harshad / Niven Perfect Square Powerful Number Year

Properties

Parity
Even
Digit count
3
Digit sum
4
Digital root
4
Palindrome
No
Divisor count
15
σ(n) — sum of divisors
961

Primality

Prime factorization: 2 4 × 5 2

Divisors & multiples

All divisors (15)
1 · 2 · 4 · 5 · 8 · 10 · 16 · 20 · 25 · 40 · 50 · 80 · 100 · 200 · 400
Aliquot sum (sum of proper divisors): 561
Factor pairs (a × b = 400)
1 × 400
2 × 200
4 × 100
5 × 80
8 × 50
10 × 40
16 × 25
20 × 20
First multiples
400 · 800 · 1,200 · 1,600 · 2,000 · 2,400 · 2,800 · 3,200 · 3,600 · 4,000

Representations

In words
four hundred
Ordinal
400th
Roman numeral
CD
Binary
110010000
Octal
620
Hexadecimal
190

Also seen as

Goldbach decomposition

Goldbach's conjecture says every even integer greater than 2 is the sum of two primes. For 400, here are decompositions:

  • 3 + 397 = 400
  • 11 + 389 = 400
  • 17 + 383 = 400
  • 41 + 359 = 400
  • 47 + 353 = 400
  • 53 + 347 = 400
  • 83 + 317 = 400
  • 89 + 311 = 400

Showing the first eight; more decompositions exist.

Unicode codepoint
Ɛ
U+0190
Uppercase letter (Lu)

UTF-8 encoding: C6 90 (2 bytes).

Lookup U+0190 on Compart ↗ Lookup on FileFormat.Info ↗
HTTP status code

HTTP 400 Bad Request — Server cannot or will not process the request due to a client error.

4xx class: Client Error.

Hex color
#000190
RGB(0, 1, 144)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.144.