Properties of the Number 21029

Twenty-One Thousand Twenty-Nine

Basics

Value: 21028 → 21029 → 21030

Parity: odd

Prime: No

Previous Prime: 21023

Next Prime: 21031

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 17 × 1237

Divisors: 1, 17, 1237, 21029

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001000100101

Octal: 51045

Duodecimal: 10205

Hexadecimal: 5225

Square: 442218841

Square Root: 145.01379244747721

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

Number of positive solutions to x²+y²+z² <= n². A253663

Beach-Williams Pell numbers of type k² + 4. A212083

Numbers k such that k! - (k-1)! - 1 is prime. A49433

Numbers n where τ(n) and n-τ(n) are perfect squares, with τ(n) the number of divisors of n (A000005). A245197

Number of solutions to n = ∑_i=1..π(n-1) c(i)*p(i) with c(i) in {-1,0,1}, p(n) = n-th prime and π = A000720. A215222

Number of aperiodic necklaces (Lyndon words) with k<=5 black beads and n-k white beads. A277629

Markoff spectrum N⁵(λ). A293173

Numbers that are palindromic in base 2 and base 16. A340559

Semiprimes of the form k² + 4. A360741

Primes of the form 8k+5 generated recursively: a(1)=5, a(n) = least prime p == 5 (mod 8) with p | 4+Q², where Q is the product of all previous terms in the sequence. A57208