Properties of the Number 21124

Twenty-One Thousand One Hundred Twenty-Four

Basics

Value: 21123 → 21124 → 21125

Parity: even

Prime: No

Previous Prime: 21121

Next Prime: 21139

Digit Sum: 10

Digital Root: 1

Palindrome: No

Factorization: 2 ² × 5281

Divisors: 1, 2, 4, 5281, 10562, 21124

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001010000100

Octal: 51204

Duodecimal: 10284

Hexadecimal: 5284

Square: 446223376

Square Root: 145.3409783921933

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 A(n,k) of rooted identity trees with n nodes and k-colored non-root nodes; square array A(n,k), n>=0, k>=0, read by antidiagonals. A255517

Number of rooted identity matched trees with n nodes. A5753

a(n) = floor(surface area of a sphere with radius n). A66644

Number of partitions p of n such that the multiplicity of (max(p) - min(p)) is a part. A240495

a(n) = sum of n-th column in array in A100452. A100454

Conjectured positive numbers which have more than one representation (m,s) as a difference s² - m⁵, m >= 1, s > 0. A177770

a(n) = 4*(5·n² - 5·n + 1). A193448

Nearest integer to 4*π*n². A322615

Least number k such that (k²+1) mod s = prime(n) where s is the sum of the distinct primes dividing k²+1, or 0 if no such k exists. A272175

Expansion of 1/((1-x)*(1-2·x)*(1-5·x)*(1-7·x)). A21124