number.wiki
Number

401

401 is a prime, odd, a calendar year.

Cousin Prime Deficient Number Prime Squarefree Year

Properties

Parity
Odd
Digit count
3
Digit sum
5
Digital root
5
Palindrome
No
Divisor count
2
σ(n) — sum of divisors
402

Primality

401 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 401
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 401)
1 × 401
First multiples
401 · 802 · 1,203 · 1,604 · 2,005 · 2,406 · 2,807 · 3,208 · 3,609 · 4,010

Representations

In words
four hundred one
Ordinal
401st
Roman numeral
CDI
Binary
110010001
Octal
621
Hexadecimal
191

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 397 (gap of 4)
  • Next prime: 409 (gap of 8)

Pair status: cousin with 397.

Unicode codepoint
Ƒ
U+0191
Uppercase letter (Lu)

UTF-8 encoding: C6 91 (2 bytes).

HTTP status code

HTTP 401 Unauthorized — Authentication is required and has failed or not been provided.

4xx class: Client Error.

Hex color
#000191
RGB(0, 1, 145)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.1.145.