Properties of the Number 9891

Nine Thousand Eight Hundred Ninety-One

Basics

Value: 9890 → 9891 → 9892

Parity: odd

Prime: No

Previous Prime: 9887

Next Prime: 9901

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 7 × 157

Divisors: 1, 3, 7, 9, 21, 63, 157, 471, 1099, 1413

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011010100011

Octal: 23243

Duodecimal: 5883

Hexadecimal: 26a3

Square: 97831881

Square Root: 99.45350672550465

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

Numbers k such that numerator(Bernoulli(2·k)/(2·k)) is different from numerator(Bernoulli(2·k)/(2·k*(2·k-1))). A90495

Triangle T(n,k) = number of forests of labeled rooted trees of height at most 1, with n labels, k of which are used for root nodes and any root may contain >= 1 labels, n >= 0, 0<=k<=n. A143396

Partial sums of A014138. A14143

Second 13-gonal numbers: a(n) = n*(11·n+9)/2. A211013

A convolution triangle of numbers obtained from A034789. A92083

a(n) is the Severi degree for curves of degree n and cogenus 2. A171108

Nonnegative values·of solutions (x, y) to the Diophantine equation x²+(x+449)² = y². A130004

Diagonal in array of n-gonal numbers A081422. A81438

Triangle read by rows: T(n,k) is the number of k-matchings of the corona K'(n) of the complete graph K(n) and the complete graph K(1); in other words, K'(n) is the graph constructed from K(n) by adding for each vertex v a new vertex v' and the edge vv'. A100862

Number of subsets of {1..n} with the same number of maximal runs (increasing by 1) as maximal anti-runs (increasing by more than 1). A385572