Properties of the Number 20943

Twenty Thousand Nine Hundred Forty-Three

Basics

Value: 20942 → 20943 → 20944

Parity: odd

Prime: No

Previous Prime: 20939

Next Prime: 20947

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 13 × 179

Divisors: 1, 3, 9, 13, 39, 117, 179, 537, 1611, 2327

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 101000111001111

Octal: 50717

Duodecimal: 10153

Hexadecimal: 51cf

Square: 438609249

Square Root: 144.71696514230803

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 k!/k#-1 is prime, where k# is the primorial function (A034386). A140293

Composite numbers k such that k!/k# - 1 is prime, where k# = primorial numbers A034386. A49421

Numbers·such that the sum of all their cyclic permutations is equal to that of all cyclic permutations of σ(x) and all cyclic permutations of Euler totient function φ(x). A247317

a(n) = 729·n - 198. A156772

Numbers m such that ∑_d∣m (τ(d)/σ(d)) is an integer h where τ(k) = the number of the divisors of k (A000005) and σ(k) = the sum of the divisors of k (A000203). A323781

Partial sums of A211681. A213299

O.g.f.: exp( ∑_n>=1 A256357(n²)*xⁿ/n ), where exp( ∑_n>=1 A256357(n)*xⁿ/n ) = 1 + ∑_n>=1 x^n² + x^2·n². A258656

Number of 7-element intersecting families of an n-element set. A51184

a(2n+1) = |a(2n) - a(2n-1)|, a(2n) = a(n) + a(n-1). A20943

Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^t+u+v) having one, three, four, five or six distinct values for every i,j,k<=n. A211579