Properties of the Number 19820

Nineteen Thousand Eight Hundred Twenty

Basics

Value: 19819 → 19820 → 19821

Parity: even

Prime: No

Previous Prime: 19819

Next Prime: 19841

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ² × 5 × 991

Divisors: 1, 2, 4, 5, 10, 20, 991, 1982, 3964, 4955

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100110101101100

Octal: 46554

Duodecimal: B578

Hexadecimal: 4d6c

Square: 392832400

Square Root: 140.78352176302454

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

Number of partitions of n in which each part occurs an odd number (or zero) times. A55922

Total number of n-digit numbers requiring 3 positive biquadrates in their representation as sum of biquadrates. A186652

G.f. A(x) satisfies: [xⁿ] A(x)ⁿ⁺¹ = [xⁿ] (1 + x·A(x)^2·n)ⁿ⁺¹ for n >= 0. A360344

Costas arrays such that the corresponding permutation is connected. A213339

Expansion of 1/(2·sqrt(1-2·x-3·x²) - 1). A115967

Numbers k such that A090086(k), the smallest pseudoprime to base k (not necessarily exceeding k), is a Carmichael number. A293203

Number of partitions of n into an even number of parts that are not multiples of 4. A339406

Number of n X 5 0..2 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other. A201274

Decimal part of n^1/11 starts with a 'nine digits' anagram. A34286

Number of nondecreasing -n..n vectors of length 3 whose dot product with some nondecreasing -n..n vector equals 3. A226411