Properties of the Number 21071

Twenty-One Thousand Seventy-One

Basics

Value: 21070 → 21071 → 21072

Parity: odd

Prime: No

Previous Prime: 21067

Next Prime: 21089

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 19 × 1109

Divisors: 1, 19, 1109, 21071

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001001001111

Octal: 51117

Duodecimal: 1023B

Hexadecimal: 524f

Square: 443987041

Square Root: 145.15853402401115

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) = [xⁿ] ∏_k>=1 (1 + k·x^k)ⁿ. A297322

Related to Fibonacci numbers, see the Formula section. A215082

a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any five consecutive digits in the sequence sum up to a prime. A152605

Number of chiral pairs of color loops of length n with exactly 3 different colors. A305542

Expansion of ∏_m>=1 (1 + m·q^m)⁷. A22635

a(n) = A215082(2·n). A215108

Expansion of (1/(1 - x))*∏_k>=1 1/(1 - x^k)^p(k), where p(k) is the number of partitions of k (A000041). A291552

G.f. A(x) satisfies: A(x)² equals the g.f. of A110630, which consists entirely of numbers 1 through 4. A112570

a(n) = (n + 1)*(6·n² + 15·n + 4)/2. A269232

G.f. A(x) satisfies: A(x) = ∏_k>=1 (1 + k·x^k*A(x)^k). A301578