Properties of the Number 20421

Twenty Thousand Four Hundred Twenty-One

Basics

Value: 20420 → 20421 → 20422

Parity: odd

Prime: No

Previous Prime: 20411

Next Prime: 20431

Digit Sum: 9

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 2269

Divisors: 1, 3, 9, 2269, 6807, 20421

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 100111111000101

Octal: 47705

Duodecimal: B999

Hexadecimal: 4fc5

Square: 417017241

Square Root: 142.90206436577463

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

G.f.: ∏_k>=1 (1+x^k)^2·k+1. A255834

Numbers k such that k³ divides 17^k² + 1. A177817

Sum of numbers in the n-th antidiagonal of the reciprocity array of 1. A259577

Floor((9n+1/n)ⁿ). A197598

a(n) = round((9·n+1/n)ⁿ). A197982

Number of 3 X 3 0..n symmetric arrays with all rows summing to floor(n·3/2). A213801

a(n) = ∑_k=0..n n^k * binomial(k+n,k). A368489

a(n) = floor(8·n³/27). A379852

Numbers n such that n·prime(n) is a pandigital number containing digits 0-9 exactly once. A272552

Numbers k such that the continued fraction for sqrt(k) has period 82. A20421