7508
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 13146
- Proper Divisor Sum (Aliquot Sum)
- 5638
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3752
- Möbius Function
- 0
- Radical
- 3754
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 26
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Number of words of length n in a certain language.at n=40A005819
- Number of columns in all directed column-convex polyominoes of area n+1.at n=8A038731
- Numbers n such that 1n1, 3n3, 7n7 and 9n9 are all primes.at n=17A059677
- Numbers of the form (10*a + b)^2 + (10*b + a)^2 with a and b less than 10, in numerical order.at n=33A061191
- Sum of next n integer interprimes (cf. A024675).at n=13A075673
- Numbers k such that 9*10^k + 7 is prime.at n=19A096774
- Positions where A000695 is a square.at n=47A114398
- G.f.: 1/(1-x) = Sum_{n>=0} a(n)*x^n/(1+x)^(n^2).at n=6A133316
- Row sums of triangle A134511.at n=16A134512
- Conjecturally, even numbers n such that every even number greater than n has more decompositions as the sum of two primes.at n=43A174327
- Triangle read by rows: T(n,k) is the number of 2-compositions of n having k 0's in the top row A 2-composition of n is a nonnegative matrix with two rows, such that each column has at least one nonzero entry and whose entries sum up to n.at n=46A181330
- Binomial row sums of the Riordan matrix (1/(1-x),x/(1-x^2)) (A046854).at n=9A191586
- Number of 9X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 9 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=11A192709
- G.f.: A(x) = 1 + Sum_{n>=1} x^(n^2) * ((1-x)^n + 1/(1-x)^n).at n=40A197707
- G.f.: Product_{n>0} ( (1+x^n)/(1-x^n) )^(n^3).at n=6A206623
- Triangle of coefficients of polynomials u(n,x) jointly generated with A210564; see the Formula section.at n=53A210563
- Triangle of coefficients of polynomials v(n,x) jointly generated with A210747; see the Formula section.at n=43A210748
- Conjectured number of digits in highest power of n with no four consecutive identical digits.at n=32A216142
- Number of ON cells at generation n of 2-D cellular automaton in which a cell is ON iff either 1, 2 or 3 of its eight neighbors were ON at previous generation, starting with a single ON cell.at n=62A246308
- Solution to Popular Computing Contest 4, the Square Spiral.at n=46A256986