Properties of the Number 19881

Nineteen Thousand Eight Hundred Eighty-One

Basics

Value: 19880 → 19881 → 19882

Parity: odd

Prime: No

Previous Prime: 19867

Next Prime: 19889

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 47 ²

Divisors: 1, 3, 9, 47, 141, 423, 2209, 6627, 19881

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100110110101001

Octal: 46651

Duodecimal: B609

Hexadecimal: 4da9

Square: 395254161

Square Root: 141

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

Squares of the squarefree semiprimes (p²*q²). A85986

a(n) = (4·n + 1)². A16814

a(n) = (6·n+3)². A16946

a(n) = (5·n + 1)². A16862

a(n) is the least k such that sopfr(k) - sopf(k) = n. A280286

Odd refactorable numbers. A36896

a(n) = (floor(sqrt(2)*10ⁿ))². A114761

a(n) = ∑_k=1..n gcd(k, n)³. A343497

Number of proper divisors of n-th even perfect number. A133033

a(n) = (10·n + 1)². A17282