Properties of the Number 21365

Twenty-One Thousand Three Hundred Sixty-Five

Basics

Value: 21364 → 21365 → 21366

Parity: odd

Prime: No

Previous Prime: 21347

Next Prime: 21377

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 5 × 4273

Divisors: 1, 5, 4273, 21365

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001101110101

Octal: 51565

Duodecimal: 10445

Hexadecimal: 5375

Square: 456463225

Square Root: 146.16771189288008

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

G.f.: ∑_n=-oo..+oo n·xⁿ * (1 - xⁿ)ⁿ. A291937

Number of integer partitions of n whose run-sums are not weakly increasing. A357865

Numbers n such that 8·9ⁿ - 1 is prime. A268356

a(n) = floor( n*(n-1)*(n-2)*(n-3)/23 ). A11933

Number of integer partitions of n whose rounded mean is > 1. Partitions with mean >= 3/2. A364059

Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 21. A51986

Number of length n+5 0..1 arrays with at most one downstep in every 5 consecutive neighbor pairs. A255989

Triangle T(n,k) with the coefficient [x^k] of the polynomial p(n,x) in row n, column k, where p(n,x) = x·p(n-1,x)-n²*p(n-2,x). A136448

G.f. A(x) satisfies: 1 = ∑_n>=0 ( (1+x)^n² - A(x)ⁿ )ⁿ. A300152

Decimal expansion of 1/361. A21365