Properties of the Number 20545

Twenty Thousand Five Hundred Forty-Five

Basics

Value: 20544 → 20545 → 20546

Parity: odd

Prime: No

Previous Prime: 20543

Next Prime: 20549

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 5 × 7 × 587

Divisors: 1, 5, 7, 35, 587, 2935, 4109, 20545

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000001000001

Octal: 50101

Duodecimal: BA81

Hexadecimal: 5041

Square: 422097025

Square Root: 143.33527130472805

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

Irregular triangular array, read by rows: T(n,k) is the sum of the products of multinomial coefficients (n₁ + n₂ + n₃ + ...)!/(n₁! * n₂! * n₃! * ...) taken k at a time, where (n₁, n₂, n₃, ...) runs over all integer partitions of n (n >= 0, 0 <= k <= A000041(n)). A309951

Number of integer partitions of n that are empty, or have smallest part dividing all the others, but do not have greatest part divisible by all the others. A343345

Sum of the squarefree parts of the partitions of n into 9 parts. A309485

Irregular triangular array, read by rows: T(n,k) is the sum of the products of distinct multinomial coefficients (n₁ + n₂ + n₃ + ...)!/(n₁! * n₂! * n₃! * ...) taken k at a time, where (n₁, n₂, n₃, ...) runs over all integer partitions of n (n >= 0, 0 <= k <= A070289(n)). A325305

a(1) = 1, a(n) = ∑_k=1..n a(n-1) + k. A103519

Expansion of 1 / ((1-x)²*(1-x²)*(1-x³)*...*(1-x¹⁰)). A288345

Coordination sequence for σ-CrFe, Position Xb. A9960

Numbers whose base-4 representation contains exactly four 0's and four 1's. A45037

Number of strings of numbers x(i=1..5) in 0..n with sum i·x(i) equal to n·5. A184705

T(n,k) = number of n X k arrays with rows being permutations of 0..k-1 and no column j greater than column j-1 in all rows (n, k >= 1). A212855