Properties of the Number 20847

Twenty Thousand Eight Hundred Forty-Seven

Basics

Value: 20846 → 20847 → 20848

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 6949

Divisors: 1, 3, 6949, 20847

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000101101111

Octal: 50557

Duodecimal: 10093

Hexadecimal: 516f

Square: 434597409

Square Root: 144.3849022578192

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

a(n+1) = a(n)-th composite number, with a(0) = 1. A6508

Triangle T(n,m) by rows: The number of tatami tilings of a 2 X n grid with dimers and 2·m monomers. A272471

Indices of primes in the 10th-order Fibonacci number sequence, A127194. A257073

Number of length 4+3 0..n arrays with some disjoint pairs in every consecutive four terms having the same sum. A247536

Numbers k such that both ∑_i=1..k i·prime(i) and ∑_i=1..k (k+1-i)*prime(i) are prime. A356178

Convolution of natural numbers >= 2 and Lucas numbers. A23549

Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 96. A31594

a(0) = a(1) = 1. a(n) = ∑_p∣n a(n-p), where the sum is over all distinct primes p that divide n. A134192

T(n,k)=Number of length n+3 0..k arrays with some disjoint pairs in every consecutive four terms having the same sum. A247533

Decimal expansion of 1/sqrt(90) = sqrt(10)/30. A20847