number.wiki
Number

191

191 is a prime, odd, a calendar year.

Deficient Number Palindrome Prime Sexy Prime Squarefree Twin Prime Year

Properties

Parity
Odd
Digit count
3
Digit sum
11
Digital root
2
Palindrome
Yes
Divisor count
2
σ(n) — sum of divisors
192

Primality

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

Divisors & multiples

All divisors (2)
1 · 191
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 191)
1 × 191
First multiples
191 · 382 · 573 · 764 · 955 · 1,146 · 1,337 · 1,528 · 1,719 · 1,910

Representations

In words
one hundred ninety-one
Ordinal
191st
Roman numeral
CXCI
Binary
10111111
Octal
277
Hexadecimal
BF

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 181 (gap of 10)
  • Next prime: 193 (gap of 2)

Pair status: twin with 193.

Unicode codepoint
¿
U+00BF
Other punctuation (Po)

UTF-8 encoding: C2 BF (2 bytes).

Hex color
#0000BF
RGB(0, 0, 191)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.191.