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Properties of the Number 21319

Twenty-One Thousand Three Hundred Nineteen

Basics

Value: 21318 → 21319 → 21320

Parity: odd

Prime: Yes

Previous Prime: 21317

Next Prime: 21323

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 21319

Divisors: 1, 21319

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101001101000111

Octal: 51507

Duodecimal: 10407

Hexadecimal: 5347

Square: 454499761

Square Root: 146.01027361114012

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 of the form k2 + 3. A49423
a(n) = 15·n2 - 9·n + 1. A134154
a(1) = 3; a(2n) = smallest prime starting (in the most significant digits) with a(2n-1) (i.e., as a right concatenation of a(2n-1) and a number with no insignificant zeros); a(2n+1) = smallest prime ending in (the least significant digits) a(2n-1). Alternate left and right concatenation yielding primes. A69615
Consider the array T(n, m) = m-th prime of the form n·i(i+1)/2 +/- 1. This sequence is the main diagonal. A125765
Prime time primes on 6-digit clocks, second definition: primes of the form HMMSS where H, MM, SS are primes, H < 24, MM and SS < 60. A295013
Primes of the form p + (p2 - 1)/8, where p is also prime. A165352
Primes p dividing every A167859(m) from m=(p-1)/2 to m=(p-1). A167860
Let F(g,p) be the frequency of g up to prime nextprime(p+1). Primes p such that F(2,p) = F(4,p) and g = 2 or 4. A274122
a(n) = A007290(n+2) - 1 = 2·C(n+2,3) - 1. A108766
Primes p such that p-2 and q are primes, where q is concatenation of binary representations of p and p-2: q = p·2L + p-2, where L is the length of binary representation of p-2: L=A070939(p-2). A232237