Properties of the Number 19887

Nineteen Thousand Eight Hundred Eighty-Seven

Basics

Value: 19886 → 19887 → 19888

Parity: odd

Prime: No

Previous Prime: 19867

Next Prime: 19889

Digit Sum: 33

Digital Root: 6

Palindrome: No

Factorization: 3 × 7 × 947

Divisors: 1, 3, 7, 21, 947, 2841, 6629, 19887

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 100110110101111

Octal: 46657

Duodecimal: B613

Hexadecimal: 4daf

Square: 395492769

Square Root: 141.02127499069067

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) is the number of labeled graphs of n vertices and k edges that have endpoints, where an endpoint is a vertex with degree 1. A245796

24-hedral numbers: a(n) = (2·n + 1)*(8·n² + 14·n + 7). A254473

a(n) = n! * ∑_k=0..n k^k·n/k!. A356689

Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 47. A31725

Triangle read by rows: T(n,k) is the number of weighted lattice paths in B(n) having k ascents. The members of B(n) are paths of weight n that start at (0,0), end on but never go below the horizontal axis, and whose steps are of the following four kinds: an (1,0)-step with weight 1, an (1,0)-step with weight 2, a (1,1)-step with weight 2, and a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps. An ascent is a maximal sequence of consecutive (1,1)-steps. A246186

Number of (n+1)X(7+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. A250728

Number of (5+1) X (n+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. A250734

Number of nX3 0..1 arrays with every element equal to 0, 1, 3, 4 or 7 king-move adjacent elements, with upper left element zero. A298496

Partial sums of A033616. A299902

Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 47. A31545