Properties of the Number 12781

Twelve Thousand Seven Hundred Eighty-One

Basics

Value: 12780 → 12781 → 12782

Parity: odd

Prime: Yes

Previous Prime: 12763

Next Prime: 12791

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 12781

Divisors: 1, 12781

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11000111101101

Octal: 30755

Duodecimal: 7491

Hexadecimal: 31ed

Square: 163353961

Square Root: 113.05308487608819

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

Mountain primes. A134951

E.g.f. exp( x*(1+x)/(1-x) ). A112242

Primes p such that A001175(p) = (p-1)/6. A308791

Primes p such that A001177(p) = (p-1)/6. A308799

Sequence of 2 Pythagorean triangles, each with a leg and hypotenuse prime. The leg of the second triangle is the hypotenuse of the first. A48270

a(2·n+1) = 9·a(n), a(2·n+2) = 10·a(n) + a(n-1). A116555

5-Ramanujan primes; the interval (x/2,x] has at least n 4-Ramanujan primes for x >= a(n) but not for x = a(n)-1. A192823

Primes p such that p²-p-1 and p²-p+1 are twin primes. A120364

a(n) = ∑_k=1..n floor(n³/k³). A344675

a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k. A24847