8225
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 11904
- Proper Divisor Sum (Aliquot Sum)
- 3679
- 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
- 5520
- Möbius Function
- 0
- Radical
- 1645
- 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
- 114
- 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
- sech(sec(x)*tan(x))=1-1/2!*x^2-15/4!*x^4-177/6!*x^6+8225/8!*x^8...at n=4A012800
- a(n) is nonsquarefree and is sum of first k nonsquarefrees for some k.at n=34A013935
- a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p diving [ A*a(n)+B ] and p=2, A=2.00013, B=3.0.at n=29A029580
- Numbers whose base-4 representation contains exactly four 0's and two 2's.at n=26A045059
- Odd numbers k such that the number of 1's in binary representation of k equals omega(k), the number of distinct primes in the factorization of k.at n=18A071595
- a(n) = 1 + C(2,1)^3 + C(4,2)^3 + ... + C(2n,n)^3.at n=3A079727
- a(1)=1, then add 1 multiply by 2 to get a(2), subtract 1 and multiply by 3 to get a(3), add 1 and multiply by 4 to get a(4) and so on.at n=6A085110
- Numbers n such that sum of n-th and (n+1)-st semiprimes is a square=q^2.at n=42A109311
- a(n) = A145812(2n-1).at n=34A145849
- Number of n X n symmetric 0..5 arrays with rows, considered as 6-ary numbers, in strictly increasing order.at n=2A162130
- Sum of a positive square and a positive cube in at least three ways.at n=14A171385
- Twin natural nonprimes with nonprime number of prime factors.at n=32A171995
- Sums of three Mersenne primes.at n=23A174055
- Numbers k such that Mordell's equation y^2 = x^3 + k has exactly 22 integral solutions.at n=3A179160
- Numbers n such that n^2 is a concatenation of two nonzero squares with no trailing zeros in n.at n=40A198035
- Sum_{k=0..n} C(2*k, k)^n.at n=2A238717
- Positive integers, c, such that there is more than one solution to the equation a^2 + b^3 = c^4, with a, b > 0.at n=34A242186
- a(1) = 1, a(n) = smallest positive number not yet in the sequence such that the concatenation of a(n-1) and a(n) is a square.at n=41A264770
- Numbers whose base-5 representation is a square when read in base 10.at n=40A267765
- Numbers k such that the decimal number 1k is a square.at n=46A272671