Properties of the Number 20939

Twenty Thousand Nine Hundred Thirty-Nine

Basics

Value: 20938 → 20939 → 20940

Parity: odd

Prime: Yes

Previous Prime: 20929

Next Prime: 20947

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 20939

Divisors: 1, 20939

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111001011

Octal: 50713

Duodecimal: 1014B

Hexadecimal: 51cb

Square: 438441721

Square Root: 144.703144402601

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

Least k>p such that (kp)³ divides (p-1)^kp²+1 for prime p = A000040(n). A128677

Irregular primes with irregularity index three. A60975

Numerators of upper primes-only best approximates (POBAs) to the golden ratio, φ (A001622); see Comments. A265798

Primes of the form 2·n²+26·n+11. A243888

Number of consecutive prime runs of 3 primes congruent to 1 mod 4 below 10ⁿ. A92642

G.f.: ∑_n>=0 (n+1) * xⁿ * (1 + xⁿ)ⁿ. A326002

Row sums of triangle A086606: the sum of the first n terms of the n-th self-convolution of the sequence formed by flattening triangle A086606. A86608

Primes that remain prime through 3 iterations of function f(x) = 3x + 2. A23277

Primes that remain prime through 4 iterations of function f(x) = 3x + 10. A23310

Primes that do not divide any term of the Lucas 4-step sequence A073817. A106300