Properties of the Number 6921

Six Thousand Nine Hundred Twenty-One

Basics

Value: 6920 → 6921 → 6922

Parity: odd

Prime: No

Previous Prime: 6917

Next Prime: 6947

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 769

Divisors: 1, 3, 9, 769, 2307, 6921

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 1101100001001

Octal: 15411

Duodecimal: 4009

Hexadecimal: 1b09

Square: 47900241

Square Root: 83.19254774317228

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

a(n) = n² written backwards. A2942

T(n,k) is the number of (n+1) X (k+1) 0..1 arrays with rows and columns of permanents of all 2 X 2 subblocks lexicographically nondecreasing. A204962

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the sum of each 2X2 subblock two extreme terms minus its two median terms lexicographically nondecreasing rowwise and columnwise. A235842

G.f. A(x) satisfies A(x) = 1 + x·A(x)³/(1 - x)². A366176

Composites for which the row of the prime-composite array (A063173) includes the leftmost element of both a zero-only antidiagonal and a zero-only diagonal(A067681). A63176

a(n) = 3·a(n-1) + 2·a(n-2) + a(n-3). A108153

E.g.f. arctan(x/cos(x)) (odd powers only). A191003

Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 541", based on the 5-celled von Neumann neighborhood. A272805

Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 557", based on the 5-celled von Neumann neighborhood. A272924

Sum of terms in level n of TRIP - Stern sequence associated with permutation triple (e,e,132). A278613