Properties of the Number 20740

Twenty Thousand Seven Hundred Forty

Basics

Value: 20739 → 20740 → 20741

Parity: even

Prime: No

Previous Prime: 20731

Next Prime: 20743

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 5 × 17 × 61

Divisors: 1, 2, 4, 5, 10, 17, 20, 34, 61, 68

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000100000100

Octal: 50404

Duodecimal: 10004

Hexadecimal: 5104

Square: 430147600

Square Root: 144.01388821915754

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

Numbers k such that k³ divides 3^k² - 1. A129211

a(n) = 2·n*Fibonacci(n-2) + (-1)ⁿ + 1. A309874

T(n,k)=Number of nXk 0..4 arrays with each element·equal to the number of its horizontal and vertical neighbors equal to 3,2,0,1,4 for x=0,1,2,3,4. A196590

Numbers containing only 1's and 0's in their base-2, base-3, and base-4 representations. A258981

T(n,k)=Number of nXk 0..4 arrays with each element·equal to the number of its horizontal and vertical neighbors equal to 3,2,0,4,1 for x=0,1,2,3,4. A196802

T(n,k)=Number of nXk 0..4 arrays with each element·equal to the number of its horizontal and vertical neighbors equal to 4,2,0,1,3 for x=0,1,2,3,4. A197047

Triangle read by rows: T(m,n) is the Szeged index of the grid graph P_m X P_n (1 <= n <= m). A245826

G.f. satisfies A(x) = exp( ∑_k>=1 (-1)^k+1 * (3 + A(x^k)) * x^k/k ). A363509

a(n) = n⁴+4 = (n²-2·n+2)*(n²+2·n+2) = ((n-1)²+1)*((n+1)²+1). A57781

a(n) = F(n)² + 4*(-1)ⁿ = F(n+3)*F(n-3), where F = A000045. A292612