Properties of the Number 28720

Twenty-Eight Thousand Seven Hundred Twenty

Basics

Value: 28719 → 28720 → 28721

Parity: even

Prime: No

Previous Prime: 28711

Next Prime: 28723

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 ⁴ × 5 × 359

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 40, 80

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111000000110000

Octal: 70060

Duodecimal: 14754

Hexadecimal: 7030

Square: 824838400

Square Root: 169.46976131451888

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

Sum of quadratic residues of (n-th prime == 3 mod 4). A282035

Column 1 of triangle A118032, where column 1 of the matrix square of A118032 forms a bisection of this sequence. A118034

Column 1 of triangle A118045; also equals a bisection of A118034, which is column 1 of A118032. A118047

Let p = n-th prime == 7 mod 8; a(n) = sum of quadratic residues mod p. A282041

a(n) = 2·n*(9·n-1). A178574

Irregular triangle read by rows: T(n,k) is the number of simple connected graphs on n unlabeled nodes with domination number k, n >= 1, 1 <= k <= A065033(n+1). A332401

Quotients arising in A073162: A046992(n)/n if n is in A073162. A73164

Somos's sequence {b(8,n)} defined in comment in A078495: a(0)=a(1)=...=a(18)=1; for n>=19, a(n)=(a(n-1)*a(n-18)+a(n-9)*a(n-10))/a(n-19). A271955

T(n,k) = Number of nondecreasing arrangements of n+3 numbers in 0..k with each number being the sum mod (k+1) of three others. A183904

Expansion of (theta₃(z)*theta₃(7z)*theta₃(49z)+theta₂(z)*theta₂(7z)*theta₂(49z))³. A28720