Properties of the Number 18681

Eighteen Thousand Six Hundred Eighty-One

Basics

Value: 18680 → 18681 → 18682

Parity: odd

Prime: No

Previous Prime: 18679

Next Prime: 18691

Digit Sum: 24

Digital Root: 6

Palindrome: Yes

Factorization: 3 × 13 × 479

Divisors: 1, 3, 13, 39, 479, 1437, 6227, 18681

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100100011111001

Octal: 44371

Duodecimal: A989

Hexadecimal: 48f9

Square: 348979761

Square Root: 136.67845477616433

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 (n+2)X(k+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001001. A259962

Denominators of continued fraction convergents to sqrt(954). A42847

Lucky numbers that are both palindromic and nonprime. A31880

Palindromic Super-2 Numbers. A32750

Numbers n for which there are exactly nine k such that n = k + reverse(k). A72433

Beginning with 2, smallest palindrome >= the previous term such that every concatenation is a prime. A88093

a(1) = 1, then the rearrangement of odd palindromes such that every concatenation is a prime for n > 1. A113578

G.f. is the polynomial (1-x³) * (1-x⁶) * (1-x⁹) * (1-x¹²) * (1-x¹⁵) * (1-x¹⁸) / (1-x)⁶. A162539

Palindromic Ulam numbers. A173542

Number of (n+2) X (3+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00001001. A259957