Properties of the Number 21705

Twenty-One Thousand Seven Hundred Five

Basics

Value: 21704 → 21705 → 21706

Parity: odd

Prime: No

Previous Prime: 21701

Next Prime: 21713

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 5 × 1447

Divisors: 1, 3, 5, 15, 1447, 4341, 7235, 21705

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010011001001

Octal: 52311

Duodecimal: 10689

Hexadecimal: 54c9

Square: 471107025

Square Root: 147.32616875490925

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

Number of integer partitions of n whose negated run-lengths are unimodal. A332638

a(n) = n⁴ + 4·n³ + 12·n² + 24·n + 24. A127878

Triangle T(n,k) = A176492(n,k) + A008292(n+1,k+1) - 1 read along rows 0<=k<=n. A176492

Starting at n, a(n) is the number of times we move from a negative position to a spot we have already visited according to the following rules. On the k-th step (k=1,2,3,...) move a distance of k in the direction of zero. If the number landed on has been landed on before, move a distance of k away. A324683

Dirichlet convolution of b_n=2^n-1 with Bell numbers. A34740

Square array of Delannoy numbers D(i,j) (i >= 0, j >= 0) read by antidiagonals. A8288

Number of (1+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 5 6 or 7. A252385

Number of 4Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors. A283860

Decimal expansion of 1/701. A21705