Properties of the Number 21191

Twenty-One Thousand One Hundred Ninety-One

Basics

Value: 21190 → 21191 → 21192

Parity: odd

Prime: Yes

Previous Prime: 21187

Next Prime: 21193

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 21191

Divisors: 1, 21191

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001011000111

Octal: 51307

Duodecimal: 1031B

Hexadecimal: 52c7

Square: 449058481

Square Root: 145.5712883778941

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

Primes having only {1, 2, 9} as digits. A385776

Decimal encoding of the prime factorization of n: concatenation of prime factors and exponents. A67599

Primes p whose reciprocal has period (p-1)/10. A56215

Primes of the form 2·n² + 74·n + 35. A217500

Primes in A065387 in the order of their appearance. A229264

Construct sequences P,Q,R by the rules: Q = first differences of P, R = second differences of P, P starts with 1,3,9, Q starts with 2,6, R starts with 4; at each stage the smallest number not yet present in P,Q,R is appended to R. Sequence gives P. A225385

Primes p such that continued fraction of (1 + sqrt(p))/2 has period 8; primes in A146333. A146353

a(n) = 49·n² - 20·n + 2. A157373

Discriminants of quintic fields with 2 complex conjugates (negated). A23684

a(1) = 11 by convention; for n > 1, if n = p^a*q^b... then a(n) = concatenate(p,a,q,b,...). A68633