Properties of the Number 21356

Twenty-One Thousand Three Hundred Fifty-Six

Basics

Value: 21355 → 21356 → 21357

Parity: even

Prime: No

Previous Prime: 21347

Next Prime: 21377

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 2 ² × 19 × 281

Divisors: 1, 2, 4, 19, 38, 76, 281, 562, 1124, 5339

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001101101100

Octal: 51554

Duodecimal: 10438

Hexadecimal: 536c

Square: 456078736

Square Root: 146.13692209705252

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

Square table T(n,k), read by antidiagonals, that satisfies T(n,0)=1, T(n+1,k+1) = sum(i=0,n, sum(j=0,k, T(n-i,k-j)*T(i,j) )), such that the top row and diagonal are equal: T(0,k)=T(k,k)=A088159(k). A88158

First row and main diagonal of square table that satisfies T(n+1,k+1) = sum(i=0,n, sum(j=0,k, T(n-i,k-j)*T(i,j) )). A88159

G.f.: ∏_m>0 (1 - x^m + 2!*x^2·m - 3!*x^3·m + 4!*x^4·m). A293256

Sum of antidiagonals of square table that satisfies T(n+1,k+1) = sum(i=0,n, sum(j=0,k, T(n-i,k-j)*T(i,j) )) such that the top row and diagonal are equal: T(0,k)=T(k,k)=A088159(k). A88160

Decimal expansion of 1/352. A21356

a(n) = n! * ∑_k=1..n binomial(2n+1,k)/k. A129840