number.wiki
Number

181

181 is a prime, odd, a calendar year.

Deficient Number Palindrome Prime Squarefree Strobogrammatic Twin Prime Year

Properties

Parity
Odd
Digit count
3
Digit sum
10
Digital root
1
Palindrome
Yes
Divisor count
2
σ(n) — sum of divisors
182

Primality

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

Divisors & multiples

All divisors (2)
1 · 181
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 181)
1 × 181
First multiples
181 · 362 · 543 · 724 · 905 · 1,086 · 1,267 · 1,448 · 1,629 · 1,810

Representations

In words
one hundred eighty-one
Ordinal
181st
Roman numeral
CLXXXI
Binary
10110101
Octal
265
Hexadecimal
B5

Also seen as

Prime neighborhood

Adjacent primes:

  • Previous prime: 179 (gap of 2)
  • Next prime: 191 (gap of 10)

Pair status: twin with 179.

Unicode codepoint
µ
U+00B5
Lowercase letter (Ll)

UTF-8 encoding: C2 B5 (2 bytes).

Hex color
#0000B5
RGB(0, 0, 181)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.181.

Possible US bank routing number

This passes the ABA routing number checksum and matches the Federal Reserve numbering scheme.

Routing number
000000181
Federal Reserve
United States Government

Banks operate many routing numbers per state and division; an unmatched checksum-valid number can still be a real RTN at a smaller institution.