Properties of the Number 21647

Twenty-One Thousand Six Hundred Forty-Seven

Basics

Value: 21646 → 21647 → 21648

Parity: odd

Prime: Yes

Previous Prime: 21617

Next Prime: 21649

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 21647

Divisors: 1, 21647

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010010001111

Octal: 52217

Duodecimal: 1063B

Hexadecimal: 548f

Square: 468592609

Square Root: 147.12919492745144

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

Primes or negative values of primes in the sequence b(n) = 47·n² - 1701·n + 10181, n >= 0. A50267

Balanced primes of order nine. A96701

Numbers k such that (8^k + 5^k)/13 is prime. A128338

Primes of the form 43·n² - 537·n + 2971 in order of increasing nonnegative values of n. A272285

Hilltop maps: number of n X 1 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal or vertical neighbor in a random 0..2 n X 1 array. A218199

Lesser member p of a twin prime pair (p, p + 2) such that 2p + 3(p + 2) is a perfect square. A174370

Primes of the form 47·n² - 1701·n + 10181. A128878

The first member of a twin prime pair whose sum equals the sums of k consecutive smaller pairs of twin primes, k=3. A226692

Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-1) + 1, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences. A294542

Lesser of twin primes p such that p and p+2 are both in A115591. A367318