7119
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 11856
- Proper Divisor Sum (Aliquot Sum)
- 4737
- 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
- 4032
- Möbius Function
- 0
- Radical
- 2373
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 49
- Smith Number
- yes
- 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
- Numbers k such that (k / product of digits of k) is 1 or a prime.at n=28A001103
- a(n) = prime(n)*(prime(n+1)-1)/2.at n=29A014303
- a(n) = 1*prime(n) + 2*prime(n-1) + ... + k*prime(n+1-k), where k=floor((n+1)/2) and prime(n) is the n-th prime.at n=27A023870
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (primes).at n=26A024867
- Minimal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.at n=24A045613
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(2) = 4.at n=29A050039
- Numbers with all odd digits, in which each digit divides the number formed by the rest, i.e., the number obtained by just removing this digit.at n=35A061507
- (Prime(n)# - 4)/2 is prime, where x# is the primorial A034386(x).at n=29A067026
- Smallest number k such that A065422(k)/A065422(k+1) = k^n, where k>1.at n=8A070970
- Numbers n such that n and the n-th prime have the same digits.at n=17A074350
- Numbers n such that 2*n*k(n) is rational but not an integer, where k(n) is sum of successive remainders when computing the Euclidean algorithm for (1, 1/sqrt(n)) as defined in A086378 (MuPAD program is given there); numbers belonging to A086378 but not to A088900.at n=7A087414
- Triangle read by rows: T(n,k) is the number of permutations p of [n] in which exactly the first k terms satisfy the up-down property, i.e., p(1)<p(2), p(2)>p(3), p(3)<p(4), ...at n=42A092580
- E.g.f.: (1/(1-x^3))*exp( 3*sum_{i>=0} x^(3*i+1)/(3*i+1) ) for an order-3 linear recurrence with varying coefficients.at n=6A097677
- Maximum determinant that can be formed from the optimal set of nonnegative 3 X 3 matrix elements <=n, which maximize the number of different determinants given in A099834.at n=18A099815
- Diagonal sums of correlation triangle for (1+x)^3/(1-x).at n=38A115294
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 1), (1, -1, -1), (1, 0, 1), (1, 1, 0)}.at n=7A150439
- Numbers k such that k^81*(k^81+1)+1 is prime.at n=32A153442
- a(n+1)-+a(n)=prime, a(n+1)*a(n)=Average of twin prime pairs, a(1)=2,a(2)=9.at n=31A154495
- Numbers n such that n^6 + 272 is prime.at n=7A161998
- Numbers k such that (k^3 + 2, n^3 + 4) is a twin prime pair.at n=41A178337