Properties of the Number 181

One Hundred Eighty-One

Basics

Value: 180 → 181 → 182

Parity: odd

Prime: Yes

Previous Prime: 179

Next Prime: 191

Digit Sum: 10

Digital Root: 1

Palindrome: Yes

Factorization: 181

Divisors: 1, 181

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10110101

Octal: 265

Duodecimal: 131

Hexadecimal: b5

Square: 32761

Square Root: 13.45362404707371

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

The prime numbers. A40

Powers of primes. Alternatively, 1 and the prime powers (p^k, p prime, k >= 1). A961

Palindromes in base 10. A2113

Prime numbers at the beginning of the 20th century (today 1 is no longer regarded as a prime). A8578

Pythagorean primes: primes of the form 4·k + 1. A2144

Greater of twin primes. A6512

Prime powers: numbers of the form p^k where p is a prime and k >= 1. A246655

Odd primes. A65091

Centered square numbers: a(n) = 2·n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values. A1844

Palindromic primes: prime numbers whose decimal expansion is a palindrome. A2385

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