Properties of the Number 28821

Twenty-Eight Thousand Eight Hundred Twenty-One

Basics

Value: 28820 → 28821 → 28822

Parity: odd

Prime: No

Previous Prime: 28817

Next Prime: 28837

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 13 × 739

Divisors: 1, 3, 13, 39, 739, 2217, 9607, 28821

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111000010010101

Octal: 70225

Duodecimal: 14819

Hexadecimal: 7095

Square: 830650041

Square Root: 169.76748805351394

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

Expansion of 1/(1 - ∑_k>=2 floor(1/ω(k))*x^k), where ω(k) is the number of distinct prime factors (A001221). A280195

Inverse hyperbinomial transform of A089467. A89466

Expansion of g.f. 1/(1 - 3·x + 2·x³). A77846

Triangle read by rows: T(n,k) (0 <= k <= n) = ∑_i=0..[k/2] (-1)ⁱ*binomial(k,2·i)*(2·i-1)!!*n^k-2·i. A244490

Number of compositions (ordered partitions) of n into parts with an odd number of distinct prime divisors. A286224

Number of compositions (ordered partitions) of n into parts having the same number of distinct prime divisors as n. A301332

Triangular array read by rows: T(n,k) is the number of functions f:{1,2,...,n} -> {1,2,...,n} that have exactly k 2-cycles for n >= 0 and 0 <= k <= floor(n/2). A185025

a(n) = 2*∑_k=0..n-1 C(n-1,k)*C(n+k,k) + n. A236407

Array read by antidiagonals: T(n,k) is the number of functions f: X->Y, where X is a subset of Y, |X| = n, |Y| = n+k, such that for every·in X, f(f(x)) ≠ x. A334014

Smallest number k >= A000043(n) such that k·A000668(n)*(k·A000668(n)+1)-1 is prime. A249509