Properties of the Number 21831

Twenty-One Thousand Eight Hundred Thirty-One

Basics

Value: 21830 → 21831 → 21832

Parity: odd

Prime: No

Previous Prime: 21821

Next Prime: 21839

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 19 × 383

Divisors: 1, 3, 19, 57, 383, 1149, 7277, 21831

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010101000111

Octal: 52507

Duodecimal: 10773

Hexadecimal: 5547

Square: 476592561

Square Root: 147.75317255477123

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

T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. A302367

a(n) = ∑_i=0..n ∑_j=0..n A026637(i,j). A26646

Zeckendorf expansion of n: repeatedly subtract the largest Fibonacci number you can until nothing remains. Big-endian concatenation of decimals. A35514

33-gonal numbers: n(31n-29)/2. A98923

Triangle read by rows: T(n, k) = qStirling1(n, k, q) for q = 2, with 0 <= k <= n. A333142

Rhombi (in 3 different orientations) in a rhombus with 60-degree acute angles. A52153

Number of nX7 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. A302366

Number of 4Xn 0..1 arrays with every element equal to 0, 2, 3 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. A302370

Decimal expansion of 1/827. A21831