Properties of the Number 19811

Nineteen Thousand Eight Hundred Eleven

Basics

Value: 19810 → 19811 → 19812

Parity: odd

Prime: No

Previous Prime: 19801

Next Prime: 19813

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 11 × 1801

Divisors: 1, 11, 1801, 19811

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 100110101100011

Octal: 46543

Duodecimal: B56B

Hexadecimal: 4d63

Square: 392475721

Square Root: 140.75155416548694

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 A(n,k) of necklaces with n white beads and k·n black beads; square array A(n,k), n>=0, k>=0, read by antidiagonals. A261494

Number of necklaces with 6 black beads and n-6 white beads. A32191

Number of elements of a Weyl group of order 2^n-1 n! of type D for which a reduced word contains all of the simple reflections. A112225

Semiprimes in A033951. A113691

Number of necklaces with n white beads and 4·n black beads. A261498

Divisors of 2⁵⁰ - 1. A3554

Denominators of continued fraction convergents to sqrt(116). A41211

Denominators of continued fraction convergents to sqrt(464). A41885

p-INVERT of the positive integers, where p(S) = 1 - S - S⁴. A290898

Starting positions of strings of three 5's in the decimal expansion of π. A83620