Properties of the Number 20516

Twenty Thousand Five Hundred Sixteen

Basics

Value: 20515 → 20516 → 20517

Parity: even

Prime: No

Previous Prime: 20509

Next Prime: 20521

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 ² × 23 × 223

Divisors: 1, 2, 4, 23, 46, 92, 223, 446, 892, 5129

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000000100100

Octal: 50044

Duodecimal: BA58

Hexadecimal: 5024

Square: 420906256

Square Root: 143.23407415835104

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

Smallest k > 0 with gcd(k, rev(k)) = n, where rev(k) is digit reversal of k, or 0 if no such k exists. A69554

Numbers m such that 5^m reversed is a prime. A58993

12-gonal (or dodecagonal) pyramidal numbers: a(n) = n*(n+1)*(10·n-7)/6. A7587

Numbers k such that k³ contains a pandigital substring. A115933

Carlitz compositions of n into odd parts. A218694

Smallest number k such that kⁿ is equal to the sum of n consecutive primes, or 1 if it does not exist. A123112

Numbers k such that (6^k)*(2^k - 1) - 1 is prime. A98863

Triangle, read by rows, T(n, k) = ∑_j=0..k (-1)^j*(k-j+1)ⁿ*binomial(n+1, j) *binomial(n+2, j)/(j+1). A176124

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 358", based on the 5-celled von Neumann neighborhood. A271412

Triangle read by rows: first define the Narayana numbers: Y(n,m)=Binomial[n, m]*Binomial[n + 1, m + 1]/(n - m + 1); then t(n,m)=Sum[(-1)^j *Y(n + 1, j)*(k + 1 - j)ⁿ, {j, 0, k + 1}]. A155796