Properties of the Number 21091

Twenty-One Thousand Ninety-One

Basics

Value: 21090 → 21091 → 21092

Parity: odd

Prime: No

Previous Prime: 21089

Next Prime: 21101

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 7 × 23 × 131

Divisors: 1, 7, 23, 131, 161, 917, 3013, 21091

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001001100011

Octal: 51143

Duodecimal: 10257

Hexadecimal: 5263

Square: 444830281

Square Root: 145.22740788157034

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

Sum of the smallest parts of the partitions of n into 10 parts. A326589

Composite numbers divisible by the palindromic sum of their prime factors (counted with multiplicity). A46358

Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 30", based on the 5-celled von Neumann neighborhood. A274487

a(n) = ∑_k=0..n binomial(floor((n+1)/2), floor((k+1)/2)) * 5^k. A97176

Odd numbers divisible by the palindromic sum of their prime factors (counted with multiplicity). A46359

Composite a(n) divided by the palindromic sum of its prime factors is a palindrome (counted with multiplicity). A46361

Number of trees with n nodes and 5 leaves. A55292

Numbers k = p·q*r (p, q, r prime) congruent to 0 mod p+q+r. A160394

Odd squarefree composite numbers k, divisible by the sum of their prime factors, sopfr (A001414). A308643

Centered 30-gonal numbers. A389799