Properties of the Number 20818

Twenty Thousand Eight Hundred Eighteen

Basics

Value: 20817 → 20818 → 20819

Parity: even

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 × 7 × 1487

Divisors: 1, 2, 7, 14, 1487, 2974, 10409, 20818

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000101010010

Octal: 50522

Duodecimal: 1006A

Hexadecimal: 5152

Square: 433389124

Square Root: 144.2844412956574

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

Triangle read by rows: T(n,k) = number of labeled graphs on n nodes with k connected components, 1<=k<=n. A143543

Number of binary carry-connected integer partitions of n. A325098

T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it, modulo 4. A239405

Diagonal in array of n-gonal numbers A081422. A81435

Expansion of ∏_k>=1 1/(1-x^k+4)^k. A263360

Number of labeled graphs on n nodes with three connected components. A323876

a(n) = ∑_{i=2..n-1, j=1..i-1, gcd(i,j)=1} (n-i)*(n-j). A332612

Number of n X 3 0..4 arrays with each element·equal to the number its horizontal and vertical neighbors equal to 3,0,4,1,2 for x=0,1,2,3,4. A196141

Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of elements above it, modulo 4. A239399

Number of 6Xn 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it, modulo 4. A239410