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Properties of the Number 21378

Twenty-One Thousand Three Hundred Seventy-Eight

Basics

Value: 21377 → 21378 → 21379

Parity: even

Prime: No

Previous Prime: 21377

Next Prime: 21379

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 2 × 3 × 7 × 509

Divisors: 1, 2, 3, 6, 7, 14, 21, 42, 509, 1018

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001110000010

Octal: 51602

Duodecimal: 10456

Hexadecimal: 5382

Square: 457018884

Square Root: 146.21217459568817

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

Triangle read by rows: T(n,k) = number of degree-n permutations with k odd cycles, k=0..n, n >= 0. A60524
Triangle T(n,k) of coefficients of Meixner polynomials of degree n, k=0..n. A60338
a(n) = minimal value of n+k (with k >= 1) such that the concatenation of the decimal digits of n,n+1,...,n+k is divisible by n+k+1, or -1 if no such n+k exists. A332584
Low-temperature magnetization expansion for Kagome net (Potts model, q=3). A57398
Triangle M(k,n) read by rows: coefficients of Meixner polynomials. A94368
a(n) = n*(n+1)*(n+2)*(n+3)*(20·n2+72·n+43)/360. A214616
Number of n X 2 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor. A201533
Numbers n such that usigma(n) = usigma(2·n+1) where usigma(n) = A034448(n). A286837
Nonsquare factors k > 0 such that k·x2 - 1 produces a new minimum of its Hardy-Littlewood constant. A331948
a(n) = start of a sequence of at least n consecutive primes, p1, p2, ..., pn (say), all == 1 mod 4, such that A(p1) > A(p2) > ... > A(pn), where A(p) (see A145010) is the area of the Pythagorean triangle with hypotenuse p. A144954