Properties of the Number 1684

One Thousand Six Hundred Eighty-Four

Basics

Value: 1683 → 1684 → 1685

Parity: even

Prime: No

Previous Prime: 1669

Next Prime: 1693

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 ² × 421

Divisors: 1, 2, 4, 421, 842, 1684

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11010010100

Octal: 3224

Duodecimal: B84

Hexadecimal: 694

Square: 2835856

Square Root: 41.036569057366385

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

Centered triangular numbers: a(n) = 3·n*(n-1)/2 + 1. A5448

Number of points on surface of tetrahedron; coordination sequence for sodalite net (equals 2·n²+2 for n > 0). A5893

a(1)=a(2)=a(3)=1, a(4)=3; thereafter a(n) = a(n-1) + a(n-3). A179070

Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n and height k (1 <= k <= n). A80936

a(n) = n² + 3. A117950

Number of partitions of n such that there is exactly one part which occurs twice, while all other parts occur only once. A90858

Number of integer partitions of n whose distinct parts are pairwise coprime. A304709

G.f. A(x) satisfies: x = ∑_n=-oo..+oo (-1)ⁿ * x^n*(n+1) * A(x)ⁿ. A355357

T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 4 6 or 7. A252640

4th binomial transform of (1,0,1,0,1,...), A059841. A81186