Properties of the Number 81661

Eighty-One Thousand Six Hundred Sixty-One

Basics

Value: 81660 → 81661 → 81662

Parity: odd

Prime: No

Previous Prime: 81649

Next Prime: 81667

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 127 × 643

Divisors: 1, 127, 643, 81661

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011111011111101

Octal: 237375

Duodecimal: 3B311

Hexadecimal: 13efd

Square: 6668518921

Square Root: 285.7638885513703

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)=Number of nXk 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1 or 2 neighboring 1s. A296386

Numbers which form a prime by appending a 3-digit odd number and form no primes by appending any 1- or 2-digit odd number not beginning with 0. A91089

Number of nX3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1 or 2 neighboring 1s. A296381

Number of nX7 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 1 or 2 neighboring 1s. A296385

Partial sums of A081660. A81661