Properties of the Number 18661

Eighteen Thousand Six Hundred Sixty-One

Basics

Value: 18660 → 18661 → 18662

Parity: odd

Prime: Yes

Previous Prime: 18637

Next Prime: 18671

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 18661

Divisors: 1, 18661

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100100011100101

Octal: 44345

Duodecimal: A971

Hexadecimal: 48e5

Square: 348232921

Square Root: 136.60527076214885

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

Primes p such that continued fraction of (1 + sqrt(p))/2 has period 15: primes in A146338. A146360

a(n) = ∑_i=0..2·n ∑_j=0..i T(i, j), where T is given by A026552. A26567

Primes of form n² + 6561. A256837

Primes p with q(p) - 1 also prime, where q(.) is the strict partition function (A000009). A234644

Primes having only {1, 6, 8} as digits. A385782

T(n,k)=Number of nXk 0..4 arrays with each element·equal to the number of its horizontal and vertical neighbors equal to 2,3,0,1,4 for x=0,1,2,3,4. A196493

Number of preferential arrangements of n labeled elements when only k <= 3 ranks are allowed. A101052

a(n) = (2·6ⁿ⁺¹ - 7) / 5. A233325

The smallest prime p that makes the pair p+/-6n both primes while no other pair of p+/-6k+6·n, 0<k<n both primes. A139602

Primes congruent to 17 mod 59. A142744