7158
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 14328
- Proper Divisor Sum (Aliquot Sum)
- 7170
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 2384
- Möbius Function
- -1
- Radical
- 7158
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 75
- 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 even period and if the last term of the periodic part is deleted the central term is 84.at n=9A031582
- Numbers n such that n^1024 + 1 is prime (a generalized Fermat prime).at n=13A057002
- Square root of coefficients of power series: A083352(x)^2 + A083352(x) - 1; term-by-term square root of A083353.at n=80A083354
- Partial sums of A084263.at n=34A084570
- Duplicate of A057002.at n=13A088360
- Beginning with 1, minimum value such that gcd(a(2n-1),a(2n)) = 1, gcd(a(2n),a(2n+1))>1 and a(n) > a(n-1).at n=48A091856
- Least positive k such that (10^n+1)^n + k is prime.at n=39A121521
- a(n) = n_t(n) where t() = triangular numbers A000217.at n=52A122627
- a(1)=1, a(n)=a(n-1)+n^0 if n odd, a(n)=a(n-1)+ n^2 if n is even.at n=34A135301
- Number of triples (p,q,r) of primes with p<q<r<=prime(n), p+q>r, q+r>p and r+p>q.at n=49A138226
- Partial sums of A003325.at n=29A139211
- a(1)=2. For n >=2, a(n) = the least integer >= a(n-1) that is not coprime to both a(n-1)+1 and a(n-1).at n=27A140525
- Number of n-digit cycles of length 3 under the Kaprekar map A151949.at n=53A164735
- Sum of pyramid weights of all dispersed Dyck paths of length n (i.e., of all Motzkin paths of length n with no (1,0) steps at positive heights).at n=13A191319
- Number of 4-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero.at n=16A208598
- Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^2>x^2+y^2.at n=24A211810
- Smallest k such that in the interval [1,k] in A242033 all odd primes <= prime(n) are present.at n=36A242036
- Smallest k such that the union of {A242033(i): 1 <= i <= k} and {A242034(i): 1 <= i <= k} includes all primes {3, ..., prime(n)}.at n=36A242064
- Partial sums of A299277.at n=19A299278
- a(n) = 110*2^n + 118.at n=6A305063