Properties of the Number 21591

Twenty-One Thousand Five Hundred Ninety-One

Basics

Value: 21590 → 21591 → 21592

Parity: odd

Prime: No

Previous Prime: 21589

Next Prime: 21599

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 2399

Divisors: 1, 3, 9, 2399, 7197, 21591

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101010001010111

Octal: 52127

Duodecimal: 105B3

Hexadecimal: 5457

Square: 466171281

Square Root: 146.9387627551015

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 (n+1)X(k+1) 0..1 arrays with every 2X2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically. A253231

Sum of squares of heptanacci numbers (Fibonacci 7-step numbers). A107245

Number of integer partitions of n whose multiplicities appear with distinct multiplicities. A325329

a(n) = ∑_i=0..n digsum₄(i)⁴, where digsum₄(i) = A053737(i). A231667

Triangle read by rows. Number T(n, k) of partitions of the multiset [1, 1, 1, 2, 2, 2, ..., n, n, n] into k nonempty submultisets, for 1 <= k <= 3n. A358721

Solution of the complementary equation a(n) = a(n-1) + a(n-2) + 2·b(n-1) - b(n-2) - 1, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4. A294425

Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically. A253225

Array A(k, n) read by descending antidiagonals: A(k, n) = ∑_m=0..n F(k, m)², where F are the k-generalized Fibonacci numbers A092921. A343138

Decimal expansion of 1/587. A21591