17557
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 17836
- Proper Divisor Sum (Aliquot Sum)
- 279
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 17280
- Möbius Function
- 1
- Radical
- 17557
- 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
- 141
- 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
- Number of permutations of length n with longest increasing subsequence of length 4.at n=4A001455
- Numbers k such that the continued fraction for sqrt(k) has period 83.at n=12A020422
- Gaps of 8 in sequence A038593 (upper terms).at n=12A038656
- Triangle of numbers T(n,k) = number of permutations of (1,2,...,n) with longest increasing subsequence of length k (1<=k<=n).at n=31A047874
- Integers n > 10583 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 10583.at n=11A066055
- a(n) = 9*n^2 + 3*n + 1.at n=44A082040
- a(n) = 16*n^2 + 4*n + 1.at n=33A082041
- Maximum value taken on by f(P) = Sum_{i=1..n} p(i)*p(n+1-i) as {p(1),p(2),...,p(n)} ranges over all permutations P of {1,2,3,...,n}.at n=37A087035
- Semiprimes in A003215.at n=31A113530
- Triangle of numbers read by rows: T(n,k) = number of permutations sigma of (1,2,...,n) with n - {length of longest increasing subsequence in sigma} = k (0<=k<=n-1).at n=32A126065
- Largest number k such that k^2 divides A007781(6n+1).at n=37A127854
- Variant of Sylvester's sequence: a(n+1) = a(n)^2 - a(n) + 1, with a(1) = 12.at n=2A144785
- Star numbers (A003154) that are also triangular numbers (A000217).at n=4A156712
- Cuban composites: composite numbers equal to the difference of two consecutive cubes.at n=41A159961
- Numbers k such that gpf(k^2+1)/k sets a new record of low value, where gpf(k) is the greatest prime dividing k (A006530).at n=21A173561
- Semiprimes p*q with p < q and 2^p (mod q) == 2^q (mod p).at n=22A179839
- Sequence of traces arising in study of Thue-Morse sequence.at n=18A201170
- Number of strict partitions of 2n having an ordering of the parts in which no two neighboring parts have the same parity.at n=36A239882
- Partial sums of A073602.at n=41A259035
- Number of permutations of [2n] with longest increasing subsequence of length n.at n=4A267433