Properties of the Number 20685

Twenty Thousand Six Hundred Eighty-Five

Basics

Value: 20684 → 20685 → 20686

Parity: odd

Prime: No

Previous Prime: 20681

Next Prime: 20693

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 7 × 197

Divisors: 1, 3, 5, 7, 15, 21, 35, 105, 197, 591

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2730 Try Today's Challenge

Representations

Binary: 101000011001101

Octal: 50315

Duodecimal: BB79

Hexadecimal: 50cd

Square: 427869225

Square Root: 143.82280764885658

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

Triangle, read by rows, that transforms diagonals in the table of coefficients of successive iterations of x*(1+x)² (cf. A166888). A166890

a(n) = n*(n+1)*(n²+1)/2. A71237

Triangle T(n,k) = A008292(n+1,k+1) + A060187(n+1,k+1)- 1 read along rows 0<=k<=n. A176490

Column 3 of triangle A166890. A166893

a(n) in base 14 is a repdigit. A48338

a(n) = n*(n+1)*(2·n³ - n² + 2)/6. A101383

Triangle T(n,k) read by rows: coefficient [x^k] of the polynomial ∑_{k=0..infinity} (2·k+1)ⁿ*binomial(x,k) / 2^x. A176668

Records in A087669. A192230

Number of ways 2 domicules can be placed on an n X n square. A243464

Pierce expansion of the cube root of 1/2. A140076