7825
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 9734
- Proper Divisor Sum (Aliquot Sum)
- 1909
- 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
- 6240
- Möbius Function
- 0
- Radical
- 1565
- 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
- 145
- 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
- G.f.: 1/((1-x)*(1-x^2)*(1-x^3)^2*(1-x^4)*(1-x^5)).at n=42A003402
- Rhombic dodecahedral numbers: a(n) = n^4 - (n - 1)^4.at n=12A005917
- a(n) = n*(n^2 + 1)/2.at n=25A006003
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite EPI = Epistilbite Ca3[Al6Si18O48].16H2O starting with a T2 atom.at n=12A019118
- Strong pseudoprimes to base 99.at n=13A020325
- Numbers k such that the continued fraction for sqrt(k) has period 15.at n=36A020354
- a(n) = n*(25*n + 1)/2.at n=25A022283
- a(n) = T(n,2n-4), T given by A027052.at n=9A027060
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 19.at n=3A031607
- "CFK" (necklace, size, unlabeled) transform of 1,2,3,4...at n=15A032141
- Expansion of 1/((1-x)*(1-x^2)^2*(1-x^3)^2*(1-x^4)^2*(1-x^5)*(1-x^6)).at n=25A045513
- Odd numbers with only palindromic prime factors whose sum is palindromic (counted with multiplicity).at n=23A046356
- Honaker's triangle problem: form a triangle with base of length n, all entries different, all row sums equal; a(n) gives minimal row sum.at n=36A047837
- a(n) = max_{r=1..n-1} ceiling(t(t(n)-t(r-1))/(n-r+1)), where t() = triangular numbers A000217.at n=36A047873
- Numbers k such that k^10 == 1 (mod 11^4).at n=5A056094
- The terms of A055237 (sums of two powers of 5) divided by 2.at n=23A073217
- Row sums of triangle A074135.at n=24A074132
- Sum of terms in each group in A074147.at n=24A074149
- Partial sums of usigma(n)^2: square of the sum of unitary divisors of n.at n=21A074789
- a(0)=1, a(1)=1, a(n) = 13*a(n/2) for n=2,4,6,..., a(n) = 12*a((n-1)/2) + a((n+1)/2) for n=3,5,7,....at n=15A116524