Properties of the Number 20975

Twenty Thousand Nine Hundred Seventy-Five

Basics

Value: 20974 → 20975 → 20976

Parity: odd

Prime: No

Previous Prime: 20963

Next Prime: 20981

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 5 ² × 839

Divisors: 1, 5, 25, 839, 4195, 20975

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111101111

Octal: 50757

Duodecimal: 1017B

Hexadecimal: 51ef

Square: 439950625

Square Root: 144.8274835796024

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

a(n) = pq + pr + qr with p = prime(n), q = prime(n+1), and r = prime(n+2). A127345

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally. A253495

Composites in A127345. A127347

Number of series-reduced achiral free pure multifunctions (with empty expressions allowed) with one atom and n positions. A317884

a(n) = 839·n. A135639

Number of asymmetric mobiles (circular rooted trees) with n nodes and 3 leaves. A55364

Expansion of φ(-x³) * f(-x, -x⁵) / ψ(x) in powers of·where φ(), ψ(), f(, ) are Ramanujan θ functions. A262614

Trajectory of n under the Reverse and Add! operation carried out in base 8 (presumably) does not reach a palindrome and (presumably) does not join the trajectory of any term m < n. A306596

On a spirally numbered square grid, with labels starting at 1, this is the number of steps that an (n,n+1) leaper makes before getting trapped, or -1 if it never gets trapped. A343178

Denominator of harmonic mean of 3 consecutive primes. Numerators are A331259. A331260