Properties of the Number 12820

Twelve Thousand Eight Hundred Twenty

Basics

Value: 12819 → 12820 → 12821

Parity: even

Prime: No

Previous Prime: 12809

Next Prime: 12821

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 5 × 641

Divisors: 1, 2, 4, 5, 10, 20, 641, 1282, 2564, 3205

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11001000010100

Octal: 31024

Duodecimal: 7504

Hexadecimal: 3214

Square: 164352400

Square Root: 113.22543883774529

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

Partial sums of A243980. A244050

T(n,k)=Number of length n+2 0..k arrays with the sum of second differences squared multiplied by some arrangement of +-1 equal to zero. A250320

Number of tilings of a 5 X n rectangle using n pentominoes of shapes L, U, X. A247125

a(n) = ∑_k=1..n (-1)^k-1 * binomial(floor(n/k)+2,3). A366395

Consider the trajectory of n under the iteration of a map which sends·to 3x - σ(x) if this is >= 0; otherwise the iteration stops. The sequence gives values of n which eventually reach 0. A37159

Where A007535 reaches a record. A98653

Least number having n orderless representations as p² + q² + r² + s², where p, q, r, and s are primes. A214513

Expansion of g.f. A(x) satisfying A(x) = 1 + 3·x*A(x)² - 2·x*A(-x)². A368635

Integers expressible as the sum of (at least two) consecutive primes in at least 4 ways. A67374

Let f(x)=(largest digit of x)^{smallest digit of x} + x (A097385). Sequence gives numbers n such that f(n) and f(n+1) are both prime. A97387