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Properties of the Number 21386

Twenty-One Thousand Three Hundred Eighty-Six

Basics

Value: 21385 → 21386 → 21387

Parity: even

Prime: No

Previous Prime: 21383

Next Prime: 21391

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 × 17 2 × 37

Divisors: 1, 2, 17, 34, 37, 74, 289, 578, 629, 1258

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 101001110001010

Octal: 51612

Duodecimal: 10462

Hexadecimal: 538a

Square: 457360996

Square Root: 146.23952953972466

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

Indices of primes in A141523. A235862
Numbers n such that sopf(n) = sopf(n-1) - sopf(n-2), where sopf(x) = sum of the distinct prime factors of x. A76527
T(n,k) = Number of n X k 0..1 arrays with every element equal to 2, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero. A299334
Greatest number m such that the fractional part of (11/10)A153685(n) <= 1/m. A153689
Greatest number m such that the fractional part of (11/10)A153686(n) <= 1/m. A153690
Number of nondecreasing sequences of n 1..7 integers with every element dividing the sequence sum. A212535
Number of nX3 0..1 arrays with every element equal to 2, 3, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero. A299329
s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (Lucas numbers). A25079
Number of nX5 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 2 neighbors with the same value. A164757
Numbers k such that 2·10k - 43 is prime. A289753