Properties of the Number 21426

Twenty-One Thousand Four Hundred Twenty-Six

Basics

Value: 21425 → 21426 → 21427

Parity: even

Prime: No

Previous Prime: 21419

Next Prime: 21433

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 × 3 × 3571

Divisors: 1, 2, 3, 6, 3571, 7142, 10713, 21426

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001110110010

Octal: 51662

Duodecimal: 10496

Hexadecimal: 53b2

Square: 459073476

Square Root: 146.37622757811462

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(n) = floor(n*φ¹⁷), where φ is the golden ratio, A001622. A4932

Numbers which are the sum of their proper divisors containing the digit 7. A59466

Number of two-rowed partitions of length 5. A70558

Number of 3-stack sortable permutations on n letters. A134664

6 times centered hexagonal numbers: 18·n*(n+1) + 6. A164016

a(n) = ∑_k=0..n T(n, k)*T(n, n+k), T given by A027960. A27984

Triangle, read by rows, where T(n,k) = n·T(n-1,k-1) + T(n-1,k-2) for n>0 and k>1, with T(n,0) = T(n-1,n-1) and T(n,1) = n·T(n-1,0) for n>0 and T(0,0) = 1. A132005

Numbers which do not reach zero under either of the iterations: x -> floor(sqrt(x)) * (x - floor(sqrt(x))²) or y -> ceiling(sqrt(y)) * (ceiling(sqrt(y))² - y). A219963

Indices of primes in sequence defined by A(0) = 83, A(n) = 10·A(n-1) - 7 for n > 0. A101062

(A192533)/2. A192534