Properties of the Number 243

Two Hundred Forty-Three

Basics

Value: 242 → 243 → 244

Parity: odd

Prime: No

Previous Prime: 241

Next Prime: 251

Digit Sum: 9

Digital Root: 9

Palindrome: No

Factorization: 3 ⁵

Divisors: 1, 3, 9, 27, 81, 243

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11110011

Octal: 363

Duodecimal: 183

Hexadecimal: f3

Square: 59049

Square Root: 15.588457268119896

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: Yes

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

Completely multiplicative with a(prime(k)) = prime(k+1). A3961

Powers of 3: a(n) = 3ⁿ. A244

Perfect powers: m^k where m > 0 and k >= 2. A1597

Powerful numbers, definition (1): if a prime p divides n then p² must also divide n (also called squareful, square full, square-full or 2-powerful numbers). A1694

The Doudna sequence: write n-1 in binary; power of prime(k) in a(n) is # of 1's that are followed by k-1 0's. A5940

3-smooth numbers: numbers of the form 2ⁱ*3^j with i, j >= 0. A3586

a(n) = ∑_k=1..n floor(n/k); also ∑_k=1..n d(k), where d = number of divisors (A000005); also number of solutions to x·y = z with 1 <= x,y,z <= n. A6218

Numbers whose base-3 representation contains no 2. A5836

1 and the prime powers p^m where m >= 2, thus excluding the primes. A25475

a(0)=1. a(n) = p(A000120(n)) * ∏_{m=1..A000120(n)} p(m)^A163510(n,m), where p(m) is the m-th prime. A163511

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