Properties of the Number 20518

Twenty Thousand Five Hundred Eighteen

Basics

Value: 20517 → 20518 → 20519

Parity: even

Prime: No

Previous Prime: 20509

Next Prime: 20521

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 × 10259

Divisors: 1, 2, 10259, 20518

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000000100110

Octal: 50046

Duodecimal: BA5A

Hexadecimal: 5026

Square: 420988324

Square Root: 143.24105556718018

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 integer partitions of n with integer reverse-alternating product. A347445

Numbers k such that the decimal digits of φ(k) are a permutation of those of k. A115921

T(n,k)=Number of length n+3 0..k arrays with no four consecutive terms having the maximum of any two terms equal to the minimum of the remaining two terms. A250387

Number of permutations which are the union of an increasing and a decreasing subsequence. A29759

Möbius transform of A324118, where A324118(n) = A000593(A156552(n)). A324542

a(n) = ∑_k=0..n Stirling2(n,k) * binomial(7·k,k) / (6·k + 1). A346768

Consider the figure made up of a row of n adjacent congruent rectangles, with diagonals of all possible rectangles drawn; a(n) = number of interior vertices where exactly three lines cross. A336489

a(0) = ... = a(3) = 1; a(n) = ∑_k=1..n-4 a(k) * a(n-k-4). A346048

a(n) = A324542(2·prime(n)). A324552

Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 98 ones. A31866