### Properties of the number 6939:

6939 = 3^{3}× 257 is the 6048

^{th}composite number and is not squarefree.

6939 has 2 distinct prime factors, 8 divisors, 7 antidivisors and 4608 totatives.

6939 = 3470

^{2}- 3469

^{2}= 1158

^{2}- 1155

^{2}= 390

^{2}- 381

^{2}= 142

^{2}- 115

^{2}is the difference of 2 nonnegative squares in 4 ways.

6939 is the sum of 2 positive triangular numbers.

6939 is the difference of 2 positive pentagonal numbers in 1 way.

6939 = 13

^{2}+ 23

^{2}+ 79

^{2}is the sum of 3 positive squares.

6939

^{2}= 864

^{2}+ 6885

^{2}is the sum of 2 positive squares in 1 way.

6939

^{2}is the sum of 3 positive squares.

6939 is a divisor of 1783

^{4}- 1.

6939 = '6' + '939' is the concatenation of 2 semiprime numbers.

6939 is palindromic in (at least) the following bases: 2, 29, and -51.

6939 in base 16 = 1b1b and consists of only the digits '1' and 'b'.

6939 in base 21 = ff9 and consists of only the digits '9' and 'f'.

6939 in base 28 = 8nn and consists of only the digits '8' and 'n'.

6939 in base 29 = 878 and consists of only the digits '7' and '8'.

### The number 6939 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.A033681: a(1) = 3; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

A048710: Family 1 "Rule 90 x Rule 150 Array" read by antidiagonals.

A068221: An auxiliary bit-mask sequence for computing A066425. (The "clean", symmetric one).

A074338: a(1) = 2; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.

A107264: Expansion of (1-3x-sqrt((1-3x)^2-4*3*x^2))/(2*3*x^2).

A107267: A square array of Motzkin related transforms, read by antidiagonals.

A111471: a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.

A195278: T(n,k)=Number of lower triangles of an n X n integer array with each element differing from all of its vertical and horizontal neighbors by k or less and triangles differing by a constant counted only once

A223556: T(n,k)=Petersen graph (3,1) coloring a rectangular array: number of nXk 0..5 arrays where 0..5 label nodes of a graph with edges 0,1 0,3 3,5 3,4 1,2 1,4 4,5 2,0 2,5 and every array movement to a horizontal or antidiagonal neighbor moves along an edge of this graph, with the array starting at 0

A249184: A249183 seen as binary numbers.

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