Properties of the Number 19521

Nineteen Thousand Five Hundred Twenty-One

Basics

Value: 19520 → 19521 → 19522

Parity: odd

Prime: No

Previous Prime: 19507

Next Prime: 19531

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ⁴ × 241

Divisors: 1, 3, 9, 27, 81, 241, 723, 2169, 6507, 19521

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100110001000001

Octal: 46101

Duodecimal: B369

Hexadecimal: 4c41

Square: 381069441

Square Root: 139.71757226634023

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

Hexanacci numbers with a(0) = ... = a(5) = 1. A383

Consider the aliquot parts, in ascending order, of a composite number. Take their sum and repeat the process deleting the minimum number and adding the previous sum. The sequence lists the numbers that after some iterations reach a sum equal to themselves. A246544

2-hyperperfect numbers: n = 2*(σ(n) - n - 1) + 1. A7593

Number of singular 2 X 2 matrices having all elements in {-n,...,n}. A209981

Odd octagonal numbers: (2n+1)*(6n+1). A14641

T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change -2,0 -1,0 0,-1 or 1,1. A264628

Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic residues mod p that are < p/2. A282721

Hyperperfect numbers: x such that x = 1 + k*(σ(x)-x-1) for some k > 0. A34897

a(1) = a(2) = 1, a(3) = 9; for n > 3, a(n) = 3·a(n-1) - 3·a(n-2) + 9·a(n-3). A101990

Hyperperfect numbers: k = m*(σ(k) - k - 1) + 1 for some m > 1. A7592