Properties of the Number 12639

Twelve Thousand Six Hundred Thirty-Nine

Basics

Value: 12638 → 12639 → 12640

Parity: odd

Prime: No

Previous Prime: 12637

Next Prime: 12641

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 11 × 383

Divisors: 1, 3, 11, 33, 383, 1149, 4213, 12639

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 11000101011111

Octal: 30537

Duodecimal: 7393

Hexadecimal: 315f

Square: 159744321

Square Root: 112.42330719205872

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

Expansion of (1 + x + x²)/(1 - x² - 2·x³). A159288

Numbers k such that (A003961(k)-2·k) divides (A003961(k)-σ(k)), where A003961 is fully multiplicative with a(prime(i)) = prime(i+1), and σ is the sum of divisors function. A378980

a(n) is the number of subsequences {s(k)} of {1,2,3,...n} such that s(k+1)-s(k) is 1 or 3. A50228

Numbers k such that A326057(k) is equal to A252748(k) and A252748(k) is not 1. A326134

G.f.: x²*(x² + x + 1)/(x⁴ - 2·x + 1). A27084

Odd numbers k for which A003961(k)-2k divides A003961(k)-σ(k), where A003961 shifts the prime factorization one step towards larger primes, and σ is the sum of divisors function. A349753

A Collatz-Fibonacci mixture: a(1) = 1, a(2) = 2, a(n+2) = a(n+1)/2+a(n)/2 if a(n+1) and a(n) have the same parity, a(n+2) = a(n+1)+a(n) otherwise. A69202

Square root of squares in A145768 (XOR of squares of the numbers 1..n). A145829

Expansion of ∏_{k > 0} (1 + A147665(k)*x^k). A147871

Expansion of (1-x+19·x³-3·x⁴)/(1-x)³. A195241