Properties of the Number 21907

Twenty-One Thousand Nine Hundred Seven

Basics

Value: 21906 → 21907 → 21908

Parity: odd

Prime: No

Previous Prime: 21893

Next Prime: 21911

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 19 × 1153

Divisors: 1, 19, 1153, 21907

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010110010011

Octal: 52623

Duodecimal: 10817

Hexadecimal: 5593

Square: 479916649

Square Root: 148.01013478812862

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

a(1)=3; for n > 1, a(n) = 1 + a(n-1) + gcd( a(n-1)*(a(n-1)+2), A073829(a(n-1)) ). A167053

Composites whose prime factorization in base 12 is an anagram of the number in base 12. A260055

Number of partitions p of n such that 2*(number of even numbers in p) > (number of odd numbers in p). A241655

a(n) = n*(7·n²-12·n+7)/2. A226451

Odd numbers k such that A064989(k) is in A340151. A340091

Numbers with sum of digits = 19, divisible by 19 and containing the string "19". A121669

a(n) is the smallest positive integer·such that x² - n! is prime. A143931

Number of binary arrays indicating the locations of trailing edge maxima of a random length-n 0..2 array extended with zeros and convolved with 1,3,3,1. A222021

G.f.: 1/(1 - x - x² - x³ + x⁵ + x⁶ + x⁷). A227376

Semiprimes of the form k² + 3. A360740