Properties of the Number 21894

Twenty-One Thousand Eight Hundred Ninety-Four

Basics

Value: 21893 → 21894 → 21895

Parity: even

Prime: No

Previous Prime: 21893

Next Prime: 21911

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 2 × 3 × 41 × 89

Divisors: 1, 2, 3, 6, 41, 82, 89, 123, 178, 246

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110000110

Octal: 52606

Duodecimal: 10806

Hexadecimal: 5586

Square: 479347236

Square Root: 147.96621235944374

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+1)X(k+1) 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..2 introduced in row major order. A231263

Expansion of (ψ(x²) / ψ(-x))³ in powers of·where ψ() is a Ramanujan θ function. A1937

Expansion of (ψ(x²) / ψ(x))³ in powers of·where ψ() is a Ramanujan θ function. A187053

Left edge of the triangle in A033291. A192735

Number of compositions of n where the smallest part is greater than or equal to the number of parts. A98131

G.f.: A(x) = 1 + ∑_n>=1 x^n² * ((1-x)ⁿ + 1/(1-x)ⁿ). A197707

Sum over the j-th term of the (n-j)-th inverse binomial transform of the Bell numbers (A000110) for all j in [n]. A361380

a(n) = 2·a(n-1) - a(n-3) for n >= 3, where a(0) = 2, a(1) = 4, a(2) = 6, a(3) = 8. A288603

Expansion of the e.g.f. log((1 - x) / (1 - 2·x)) / (1 - x)⁵. A355414

Number of (n+1)X(6+1) 0..2 arrays with no element unequal to a strict majority of its horizontal and antidiagonal neighbors, with values 0..2 introduced in row major order. A231261