Properties of the Number 21604

Twenty-One Thousand Six Hundred Four

Basics

Value: 21603 → 21604 → 21605

Parity: even

Prime: No

Previous Prime: 21601

Next Prime: 21611

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 11 × 491

Divisors: 1, 2, 4, 11, 22, 44, 491, 982, 1964, 5401

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010001100100

Octal: 52144

Duodecimal: 10604

Hexadecimal: 5464

Square: 466732816

Square Root: 146.98299221338502

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

Number of dissectable polyhedra with n tetrahedral cells with symmetry of type N or chiral pairs with symmetry of type O. A47766

a(n) = number of regions in the configuration A290447(n). A290865

Number of dissectable polyhedra with n tetrahedral cells and symmetry of type H. A47754

Let A(n) = #{(i,j): i² + j² <= n}, V(n) = π*n, P(n) = A(n) - V(n); sequence gives values of n where |P(n)| sets a new record. A99

Number of chiral pairs of dissectable polyhedra with n tetrahedral cells and symmetry of type M. A47769

Number of chiral pairs of dissectable polyhedra with n tetrahedral cells and symmetry of type C. A47774

Index of Mersenne number A000225 that is also Mersenne prime A000668, minus n-th prime: a(n) = A000043(n) - A000040(n). A153801

Number of line segments connecting exactly 3 points in an n X n grid of points. A177719

a(n) = A047752(12n+5). A47755

Numbers k such that 9·10^k + 7 is prime. A96774