Properties of the Number 21639

Twenty-One Thousand Six Hundred Thirty-Nine

Basics

Value: 21638 → 21639 → 21640

Parity: odd

Prime: No

Previous Prime: 21617

Next Prime: 21647

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 7213

Divisors: 1, 3, 7213, 21639

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010000111

Octal: 52207

Duodecimal: 10633

Hexadecimal: 5487

Square: 468246321

Square Root: 147.10200542480717

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 non-isomorphic achiral multiset partitions of weight n. A330223

T(n,k)=Number of (n+1)X(k+1) 0..1 arrays x(i,j) with row sums sum{j²*x(i,j), j=1..k+1} nondecreasing, and column sums sum{i²*x(i,j), i=1..n+1} nondecreasing. A232877

Write fundamental unit for real quadratic field of discriminant n as x + y*ω; sequence gives values of·for n == 1 mod 4. A53370

Dirichlet convolution of the integer partition numbers A000041 with the number of divisors function A000005. A323766

Number of partitions of n plus number of divisors of n. A195364

Column 1 of triangle A052311. A52312

Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 98. A31596

Number of (n+1)X(4+1) 0..1 arrays x(i,j) with row sums sum{j²*x(i,j), j=1..4+1} nondecreasing, and column sums sum{i²*x(i,j), i=1..n+1} nondecreasing. A232874

Let k = A379336(n). Then a(n) = sum of divisors d | k such that d neither divides nor is coprime to k/d, and k/d does not divide d. A378877

Decimal expansion of 1/635. A21639