7178
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11172
- Proper Divisor Sum (Aliquot Sum)
- 3994
- 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
- 3456
- Möbius Function
- -1
- Radical
- 7178
- Omega Function (Ω)
- 3
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 70
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 9.at n=39A010339
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (natural numbers >= 2), t = (Lucas numbers).at n=13A024310
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n-k+1), where k = [ n/2 ], s = (natural numbers >= 2), t = (Lucas numbers).at n=12A024873
- a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049735.at n=18A049738
- Number of basis partitions of n+16 with Durfee square size 4.at n=40A053798
- a(n) = (n^3 + 5*n + 18)/6.at n=37A060163
- Integers k such that prime(k)-1 == 0 (mod phi(k)) where prime(n)=A000040(n) is the n-th prime and phi(n)=A000010(n) is the Euler totient function.at n=48A066936
- The number of possible values of the squarefree kernel (A007947) shared by at least two solutions x to A056239(x) = n.at n=44A088318
- Least positive integer that can be represented as sum of a semiprime and a square in exactly n ways.at n=46A101181
- Expansion of x*(1 + x^2 - x^3) / ( (1-x)*(1-x-x^4) ).at n=26A168639
- Partial sums of Pillai primes (A063980).at n=31A172034
- Partial sums of ceiling(n^2/6).at n=50A175812
- Number of numerical semigroups of multiplicity n and genus n+2.at n=35A180739
- a(n)= least number k > a(n-1) such that k*(2^p-1)*(k*(2^p-1)+1)-1 is prime, where p = A000043(n) = Mersenne exponents.at n=20A200655
- Numbers which are the sum of two squared primes in exactly two ways (ignoring order).at n=38A226539
- The number of partitions of n which represent Chomp positions with Sprague-Grundy value 10.at n=51A284784
- Expansion of Product_{k>=1} 1/(1 - x^(k*(k+1)/2))^2.at n=33A298435
- Partitions of n with parts having at most 3 distinct magnitudes.at n=52A309058
- Indices of primes followed by a gap (distance to next larger prime) of 36.at n=31A320716
- G.f.: Sum_{n>=0} binomial((n+1)*(2*n+1),n)/(2*n+1) * x^n / C(x)^(n*(2*n+1)+1), where C(x) = 1 + x*C(x)^2 is the Catalan function (A000108).at n=4A352700