17665
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 21204
- Proper Divisor Sum (Aliquot Sum)
- 3539
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 14128
- Möbius Function
- 1
- Radical
- 17665
- Omega Function (Ω)
- 2
- 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
- 79
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 91.at n=8A020430
- Expansion of sum ( q^n / product( 1-q^k, k=1..5*n), n=0..inf ).at n=30A035297
- Numbers whose base-4 representation contains exactly four 0's and four 1's.at n=16A045037
- Number of rooted trees with n nodes and 3 leaves.at n=28A055278
- Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 21 (most significant digit on right).at n=12A061950
- a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A000984(k) = C(2*k,k) equals n.at n=25A081393
- a(n) is the smallest value of k such that number of non-unitary prime divisors of k-th Catalan number, A000108(k) = C(2*k,k)/(k+1) equals n.at n=24A081395
- Denominators of continued fraction convergents to (sqrt(37)-4)/3.at n=12A082975
- Indices of primes in sequence defined by A(0) = 73, A(n) = 10*A(n-1) - 17 for n > 0.at n=4A101131
- The first n primes, connected by, from left to right, alternating + and * signs.at n=21A106215
- a(n) = A145818(2n-1).at n=44A145850
- Least number having exactly two odd prime factors that differ by 2*n^2.at n=41A190052
- Numbers k such that (26*10^k + 49)/3 is prime.at n=21A282536
- Lexicographically earliest sequence of distinct terms > 0 such that the sum a(n) + a(n+1) is a substring of the concatenation (a(n), a(n+1)).at n=38A359482