Properties of the Number 21530

Twenty-One Thousand Five Hundred Thirty

Basics

Value: 21529 → 21530 → 21531

Parity: even

Prime: No

Previous Prime: 21529

Next Prime: 21557

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 2 × 5 × 2153

Divisors: 1, 2, 5, 10, 2153, 4306, 10765, 21530

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010000011010

Octal: 52032

Duodecimal: 10562

Hexadecimal: 541a

Square: 463540900

Square Root: 146.7310464761974

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

T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the central row and the central column and the two maximums of the diagonal and antidiagonal nondecreasing horizontally and vertically. A254361

Number of partitions p of n not including floor(mean(p)) as a part. A241335

Numbers n such that σ(n)=2n-φ(φ(n)). A110073

Number of permutations of length n which avoid the patterns 312, 1324, 3421; or avoid the patterns 312, 1324, 2341, etc. A116722

Number of nondecreasing arrangements of 6 numbers x(i) in -(n+4)..(n+4) with the sum of sign(x(i))*2^|x(i)| zero. A187990

Coefficient array for powers of x² of polynomials appearing in a generalized Melham conjecture on alternating sums of fifth powers of Chebyshev S polynomials with odd indices. A220671

Numbers that contain as proper substrings every maximal prime power dividing them. A59401

Expansion of 1/(1-2·x-3·x²-2·x³). A77833

Number of nX5 0..4 arrays with each element·equal to the number its horizontal and vertical neighbors equal to 2,2,1,1,1 for x=0,1,2,3,4. A197542

Number of (n+2)X(2+2) 0..1 arrays with every 3X3 subblock sum of the two medians of the central row and the central column and the two maximums of the diagonal and antidiagonal nondecreasing horizontally and vertically. A254355