Properties of the Number 19921

Nineteen Thousand Nine Hundred Twenty-One

Basics

Value: 19920 → 19921 → 19922

Parity: odd

Prime: No

Previous Prime: 19919

Next Prime: 19927

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 11 × 1811

Divisors: 1, 11, 1811, 19921

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100110111010001

Octal: 46721

Duodecimal: B641

Hexadecimal: 4dd1

Square: 396846241

Square Root: 141.14177269681716

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

Number of labeled partitions of (n,n) into pairs (i,j). A108459

Least k such that the k-th squarefree number has binary expansion of length n. Index of the smallest squarefree number >= 2ⁿ. A372540

Least k such that the k-th squarefree number has exactly n zeros in its binary expansion. A372473

Number of partitions of the set {1,2,...,n} having no blocks that contain only odd entries. A124421

E.g.f. tan(x)*exp(x). A9739

Boustrophedon transform of (n+1) mod 2. A62272

Triangle read by rows: T(n,k) is the number of partitions of the set {1,2,...,n}, having exactly k blocks consisting only odd entries (0<=k<=ceiling(n/2)). A124420

Triangle read by rows: T(n,k) is the number of partitions of the set {1,2,...,n}, having exactly k blocks consisting only even entries (0<=k<=floor(n/2)). A124422

Number of partitions of the set {1,2,...,n} having no blocks that contain only even entries. A124423

Expansion of tan(x)*cosh(x). A3719