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Properties of the Number 20639

Twenty Thousand Six Hundred Thirty-Nine

Basics

Value: 20638 → 20639 → 20640

Parity: odd

Prime: Yes

Previous Prime: 20627

Next Prime: 20641

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 20639

Divisors: 1, 20639

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000010011111

Octal: 50237

Duodecimal: BB3B

Hexadecimal: 509f

Square: 425968321

Square Root: 143.66279963859816

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

Prime(n) and prime(n+4) use the same digits. A69796
Primes such that the sum of the factorials of the digits is a perfect square. A52279
Incorrect duplicate of A297408. A7355
Primes of form ∑k=1..n (prime(k)+1). A62736
Primes p such that googol - p is prime. A108252
Lesser of a twin-prime pair where both are expressible as the sum of two triangular numbers. A118638
Primes p such that p+2 is prime and p+A001414(p+1)+(p+2) is prime. A330488
a(0) = 1; a(n) = ∑k=0..floor(n/4) binomial(n-3·k,k) * a(k). A352041
Primes congruent to 21 mod 61. A142819
Expansion of ∏k>=1 (1 - k·xk) / (1 + xk). A269339