7918
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12312
- Proper Divisor Sum (Aliquot Sum)
- 4394
- 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
- 3816
- Möbius Function
- -1
- Radical
- 7918
- 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
- 145
- 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
- Nearest integer to Gamma(n + 1/2)/Gamma(1/2).at n=8A020045
- Integer part of Gamma(n+1/2)/Gamma(1/2).at n=8A020090
- Numbers k such that the continued fraction for sqrt(k) has period 70.at n=25A020409
- a(n) = [ 2nd elementary symmetric function of {sqrt(k+1)} ], k = 1,2,...,n.at n=30A025219
- COMPOSE primes with primes.at n=5A030278
- Number of Dyck n-paths starting U^mD^m (an m-pyramid), followed by a pyramid-free Dyck path.at n=11A035929
- Numbers whose base-4 representation contains exactly three 2's and three 3's.at n=34A045151
- Numbers whose base-5 representation contains exactly two 2's and three 3's.at n=31A045273
- Number of nodes at n-th level in tree in which top node is 1; each node k has children labeled k, k+1, ..., (k+1)^2 at next level.at n=3A058311
- McKay-Thompson series of class 20D for Monster.at n=44A058553
- Number of 1's in binary expansion of parts in all partitions of n.at n=21A066624
- Numbers k >= 1 such that f(k) = k^k - (k-1)^(k-1) is prime.at n=9A072164
- Number of Fibonacci numbers F(k), k <= 10^n, whose initial digit is 5.at n=4A073561
- Non-balanced numbers in A015771.at n=13A078549
- Numbers k such that p(k), p(k)+6, p(k)+12, p(k)+18 are consecutive primes, where p(k) denotes k-th prime.at n=27A090832
- Numbers n such that p(n),p(n)+6,p(n)+12,p(n)+18 are consecutive primes and p(n)=6*k+1 for some k, where p(n) denotes n-th prime.at n=13A090838
- Numbers k such that the numerator of Bernoulli(2k) is divisible by the square of 37, the first irregular prime.at n=28A092230
- Expansion of Im(x/(1 - x - 2*i*x^2)), i=sqrt(-1).at n=17A106202
- McKay-Thompson series of class 40B for the Monster group.at n=44A112179
- a(0)=0. a(n) = a(n-1) + sum of positive integers which are <= n and not part of the sequence.at n=37A129694