Properties of the Number 20687

Twenty Thousand Six Hundred Eighty-Seven

Basics

Value: 20686 → 20687 → 20688

Parity: odd

Prime: No

Previous Prime: 20681

Next Prime: 20693

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 137 × 151

Divisors: 1, 137, 151, 20687

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000011001111

Octal: 50317

Duodecimal: BB7B

Hexadecimal: 50cf

Square: 427951969

Square Root: 143.8297604809241

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

T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock having one or three distinct values, and new values 0..2 introduced in row major order. A210107

Positive fundamental solution y(n) of the generalized Pell equation X² - D(n) Y(n) = 2 with D(n) = A261246(n). A261248

a(n) = prime(n)*prime(n+3). A90090

S₉ sequence in partition of integers > 1 described in A240521. A240536

Sequence of pairwise relatively prime numbers of class P₆ (see comment in A275246). A275251

y-value of the smallest solution to x² - p·y² = 2*(-1)^(p+1/4), p = A002145(n). A306566

Denominators of continued fraction convergents to sqrt(271). A41509

Numbers k such that 2^k + 3·k is prime. A93988

Composite numbers n such that σ(n+24) = σ(n) + 24. A54983

Values of b such that (c+9b)*prime(n)#-1 is the least prime such that (c+kb)*prime(n)#-1 are all primes for 0 <= k <= 9, or 0 if there is no solution with c+9b < prime(n)#. A188367