7526
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11664
- Proper Divisor Sum (Aliquot Sum)
- 4138
- 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
- 3640
- Möbius Function
- -1
- Radical
- 7526
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- 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
- 39
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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 partially achiral planted trees with n nodes.at n=18A003237
- Even pentagonal numbers.at n=35A014633
- Number of plane regions after drawing (in general position) a convex n-gon and all its diagonals.at n=20A027927
- Pentagonal numbers with odd index: a(n) = (2*n+1)*(3*n+1).at n=35A033570
- Write 1,2,... in a clockwise spiral; sequence gives numbers on positive x axis.at n=43A033951
- Consider all integer triples (i,j,k), j,k>0, with i^3=j^3+binomial(k+2,3), ordered by increasing i; sequence gives i values.at n=17A054234
- a(n) = T(n,n-4), array T as in A055801.at n=41A055804
- Number of permutations p of 1,2,...,n such that the denominator of the continued fraction [p(1); p(2),...,p(n)] is prime.at n=7A078432
- Least positive integer multiples of angle x such that their direction cosines form a unit vector: Sum_{k>0} cos(a(k)*x)^2 = 1, where a(1)=1, a(n+1)>a(n) and x=5/4.at n=38A080198
- Triangle read by rows: T(n,k) is the number of Motzkin paths of length n and having k peaks at odd height.at n=51A097891
- Pentagonal numbers (A000326) whose digit reversal is a prime.at n=10A115707
- Pentagonal numbers with prime indices.at n=19A116995
- Pentagonal numbers > 0 which are not the difference of two larger pentagonal numbers.at n=15A136113
- Least pentagonal number P(m) > P(n) such that P(m)+P(n) is again a pentagonal number, 0 if no such m exists.at n=20A136114
- Number of different fixed (possibly) disconnected tetrominoes bounded tightly by an n X n square.at n=6A163434
- G.f. x^4*(2*x^2-1)/( (x^2-1)*(x^2+x-1)*(2*x^3-2*x^2+2*x-1) ).at n=20A175378
- Partial sums of A050705.at n=43A177791
- Coefficient of x in the reduction of the polynomial (2*x + 1)^n by x^3 -> x^2 + x + 1.at n=7A192815
- Number of isomorphism classes of reduced Witt rings of fields with 2n orderings.at n=19A213331
- Number of isomorphism classes of reduced Witt rings of fields with n orderings.at n=39A213332