Properties of the Number 18561

Eighteen Thousand Five Hundred Sixty-One

Basics

Value: 18560 → 18561 → 18562

Parity: odd

Prime: No

Previous Prime: 18553

Next Prime: 18583

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 23 × 269

Divisors: 1, 3, 23, 69, 269, 807, 6187, 18561

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100010000001

Octal: 44201

Duodecimal: A8A9

Hexadecimal: 4881

Square: 344510721

Square Root: 136.23876100434853

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

Recursively defined polynomials, read by row. A109086

Pisot sequences E(5,7), P(5,7). A20711

Triangle of coefficients of polynomials u(n,x) jointly generated with A210752; see the Formula section. A210751

a(n) gives the odd leg of one of the two Pythagorean triangles with hypotenuse A080109(n) = A002144(n)². This is the smaller of the two possible odd legs. A253802

Number of nX2 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero. A317759

Pisot sequences E(7,10), P(7,10). A20721

Expansion of (1-x)^-1/(1+x-2·x²+x³). A77899

Derived from the centered polygonal numbers: start with the first triangular number, then the sum of the first square number and the second triangular number, then the sum of first pentagonal number, the second square number and the third triangular number, and so on and so on... A141534

Number of (6+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 3 5 6 or 7. A252390

Number of (4+1) X (n+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically. A258557