Properties of the Number 21075

Twenty-One Thousand Seventy-Five

Basics

Value: 21074 → 21075 → 21076

Parity: odd

Prime: No

Previous Prime: 21067

Next Prime: 21089

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 5 ² × 281

Divisors: 1, 3, 5, 15, 25, 75, 281, 843, 1405, 4215

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001001010011

Octal: 51123

Duodecimal: 10243

Hexadecimal: 5253

Square: 444155625

Square Root: 145.17231140957975

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 partitions p of n such that (number of numbers in p of form 3k+2) < (number of numbers in p of form 3k). A241740

Number of partitions of an n-set without blocks of size 7. A343667

a(n) = round(n*φ¹⁴), where φ is the golden ratio, A001622. A4949

McKay-Thompson series of class 12a for Monster. A58489

a(n) is the denominator of the resistance R(n) = A338401(n)/a(n) of a triangular network of 3·n*(n+1)/2 one Ohm resistors in a hexagonal lattice arrangement. A338402

"DIK" (bracelet, indistinct, unlabeled) transform of 5,5,5,5... A32286

Number of ternary rooted trees with n nodes and height exactly 6. A36421

Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 13 (most significant digit on right). A61966

a(n) = n * (n+1)² * (3·n² + 4·n + 2) / 12. A132122

a(n) = ceiling(n*φ¹⁴), where φ is the golden ratio, A001622. A4969