Properties of the Number 6681

Six Thousand Six Hundred Eighty-One

Basics

Value: 6680 → 6681 → 6682

Parity: odd

Prime: No

Previous Prime: 6679

Next Prime: 6689

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 17 × 131

Divisors: 1, 3, 17, 51, 131, 393, 2227, 6681

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1101000011001

Octal: 15031

Duodecimal: 3A49

Hexadecimal: 1a19

Square: 44635761

Square Root: 81.73738434767778

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 intersection points of all lines through pairs of vertices of a regular n-gon. A146212

10-gonal (or decagonal) pyramidal numbers: a(n) = n*(n + 1)*(8·n - 5)/6. A7585

Number of bracelets (turnover necklaces) of n beads of 2 colors, 5 of them black. A32279

T(n,k)=Number of 0..2 arrays of length n+2·k-1 with sum less than 2·k in any length 2k subsequence (=less than 50% duty cycle). A212729

Composite numbers k coprime to 13 such that k divides A006190(k-Kronecker(13,k)). A327653

a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 4's. A48537

a(n) = 3·a(n-2) - a(n-3), with a(0)=0, a(1)=a(2)=-3. A215665

Number of integer partitions of n > 0 that are not the first sums of any composition with all parts > 1. A391620

Variant of triangle A008301, read by rows of 2·n+1 terms, such that the first column is the secant numbers (A000364). A125053

Odd integers that do not generate monotonically decreasing infinitary aliquot sequences. A127667