Properties of the Number 247

Two Hundred Forty-Seven

Basics

Value: 246 → 247 → 248

Parity: odd

Prime: No

Previous Prime: 241

Next Prime: 251

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 13 × 19

Divisors: 1, 13, 19, 247

Polygonal

Triangular: No

Square: No

Pentagonal: Yes

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11110111

Octal: 367

Duodecimal: 187

Hexadecimal: f7

Square: 61009

Square Root: 15.716233645501712

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

Pentagonal numbers: a(n) = n*(3·n-1)/2. A326

Triangle of Eulerian numbers T(n,k) (n >= 1, 1 <= k <= n) read by rows. A8292

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

Generalized pentagonal numbers: m*(3·m - 1)/2, m = 0, +-1, +-2, +-3, .... A1318

Numbers whose base-3 representation contains no 2. A5836

Number of rooted identity trees with n nodes (rooted trees whose automorphism group is the identity group). A4111

Eulerian numbers (Euler's triangle: column k=2 of A008292, column k=1 of A173018). A295

a(n) = 6·n + 1. A16921

Euler's triangle: triangle of Eulerian numbers T(n,k) (n>=0, 0 <= k <= n) read by rows. A173018

Odd semiprimes: odd numbers divisible by exactly 2 primes (counted with multiplicity). A46315