7525
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 10912
- Proper Divisor Sum (Aliquot Sum)
- 3387
- 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
- 5040
- Möbius Function
- 0
- Radical
- 1505
- Omega Function (Ω)
- 4
- 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
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- yes
- 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
- 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
- no
- Odd
- yes
Appears in sequences
- Number of equivalence classes of nonzero regular 0-1 matrices of order n.at n=8A000519
- a(n) = (n+1)*(n^2+n+2)/2; g.f.: (1 + 2*x^2) / (1 - x)^4.at n=24A006000
- 4-dimensional analog of centered polygonal numbers. Also number of regions created by sides and diagonals of a convex n-gon in general position.at n=22A006522
- A subclass of 2n-node trivalent planar graphs without triangles.at n=7A006798
- Numbers k that divide s(k), where s(1)=1, s(j)=21*s(j-1)+j.at n=28A014872
- Numbers k such that the continued fraction for sqrt(k) has period 56.at n=32A020395
- When squared gives number composed of digits {2,5,6}.at n=11A030486
- Second 10-gonal (or decagonal) numbers: n*(4*n+3).at n=43A033954
- Number of rooted identity trees with n nodes and 4 leaves.at n=10A055329
- Numbers k that divide 8^k + 7^k + 6^k + 5^k + 4^k + 3^k + 2^k.at n=26A057490
- Number of partitions of a set of n elements where the partitions are of size > 3.at n=12A057837
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 71 ).at n=36A063344
- Numbers k such that k divides the numerator of B(2k) (the Bernoulli numbers), but gcd(3k, 8^k+1) > 3.at n=16A070192
- Multiples of 7 using only prime digits (2, 3, 5 and 7).at n=43A077536
- -21*zeta_K(-1), where K runs through the simplest cubic fields.at n=6A084711
- a(n) = A063997(n)/4.at n=23A088406
- Numbers n which when converted to base 6, reversed and converted back to base 10 yield a number m such that n mod m = 0. Cases which are trivial or result in digit loss are excluded.at n=3A091080
- Triangle read by rows: counts Motzkin paths by length of final descent.at n=51A098979
- Nonprimes k such that 7^k == 7 (mod k).at n=34A122784
- Numbers n such that the sum of the proper divisors of n and n+1 equals either n or n+1.at n=17A130776