Properties of the Number 13665

Thirteen Thousand Six Hundred Sixty-Five

Basics

Value: 13664 → 13665 → 13666

Parity: odd

Prime: No

Previous Prime: 13649

Next Prime: 13669

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 911

Divisors: 1, 3, 5, 15, 911, 2733, 4555, 13665

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11010101100001

Octal: 32541

Duodecimal: 7AA9

Hexadecimal: 3561

Square: 186732225

Square Root: 116.8973909033046

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

Pseudoprimes to base 7. A5938

This table shows the coefficients of sum formulas of n-th Fibonacci numbers (A000045). The k-th row (k>=1) contains T(i,k) for i=1 to k, where k=[2·n+1+(-1)^n-1]/4 and T(i,k) satisfies F(n)= ∑_i=1..k T(i,k) * n^k-i/(k-1)!. A99731

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively. A203728

Euler pseudoprimes to base 7: composite integers such that abs(7^{(n - 1}/2)) == 1 mod n. A262054

Antidiagonal sums of the antidiagonals of Losanitsch's triangle. A102543

Numbers k such that ∑_j=1..k-1 (2·j)!/4^j is an integer. A216042

Expansion of 1/(1 - x*∏_k>=1 1/(1 + k·x^k)). A299210

Number of incongruent ways to tile a 2 X n room with 1 X 2 Tatami mats. At most 3 Tatami mats may meet at a point. A68927

a(n) = 49n² - 28n - 20. A118058

Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of B(x)^k, where B(x) is the g.f. of A381570. A381569