Properties of the Number 28781

Twenty-Eight Thousand Seven Hundred Eighty-One

Basics

Value: 28780 → 28781 → 28782

Parity: odd

Prime: No

Previous Prime: 28771

Next Prime: 28789

Digit Sum: 26

Digital Root: 8

Palindrome: No

Factorization: 17 × 1693

Divisors: 1, 17, 1693, 28781

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111000001101101

Octal: 70155

Duodecimal: 147A5

Hexadecimal: 706d

Square: 828345961

Square Root: 169.64963896218583

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

Triangle T(n,k) of the number of unlabeled graphs on n nodes with universal reconstruction number k, 3<=k<=n. URN(G) is the minimum size for which all multisubsets of vertex-deleted subgraphs of G can uniquely reconstruct G up to isomorphism. A124003

a(n) = ∑_k=1..n k²*tau₃(k), where tau₃ is A007425. A319088

Number of positive integers <= 2ⁿ of form 5 x² + 10 y². A54180

Number of steps in base n after which all digits > 0 are present in x(i) where x(i) = x(i-1) + sum of missing digits of x(i-1) with x(0) = 0. A246426

Numbers k such that (28·10^k - 13) / 3 is prime. A262937

Number of (n+2)X6 binary arrays avoiding patterns 001 and 000 in rows and columns. A202597

Nonsquares mod 68. A28781