Properties of the Number 21361

Twenty-One Thousand Three Hundred Sixty-One

Basics

Value: 21360 → 21361 → 21362

Parity: odd

Prime: No

Previous Prime: 21347

Next Prime: 21377

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 41 × 521

Divisors: 1, 41, 521, 21361

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001101110001

Octal: 51561

Duodecimal: 10441

Hexadecimal: 5371

Square: 456292321

Square Root: 146.15402833996743

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

Pseudoprimes to base 5. A5936

Euler pseudoprimes to base 5: composite integers such that abs(5^{(n - 1}/2)) == 1 mod n. A262052

28-gonal numbers: a(n) = n*(13·n - 12). A161935

T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. A303410

Base-5 Euler-Jacobi pseudoprimes: odd composite k coprime to 5 such that 5^(k-1/2) == (5/k) (mod n), where (5/k) is the Jacobi symbol (or Kronecker symbol). A375914

Composite numbers k == 1, 9 (mod 10) such that 5^(k-1/2) == 1 (mod k). A375915

Number of permutations of length n which avoid the patterns 321, 2143, 3124; or avoid the patterns 132, 2314, 4312, etc. A116731

Terms of A122782 which are not Carmichael numbers A002997. A153515

Positive numbers y such that y² is of the form x² + (x+31)² with integer x. A157646

Wiener index of a benzenoid consisting of a double-step spiral chain of n hexagons (n>=2, s=21; see the Gutman et al. reference). A193397