7911
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
- 8
- Divisor Sum
- 11760
- Proper Divisor Sum (Aliquot Sum)
- 3849
- 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
- 5256
- Möbius Function
- 0
- Radical
- 879
- Omega Function (Ω)
- 4
- 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
- 75
- Smith Number
- no
- 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
- Partial sums of A006206.at n=22A001461
- Number of series-reduced planted trees with n+9 nodes and 4 internal nodes.at n=25A001860
- A generalized partition function.at n=20A002598
- Number of partitions in parts not of the form 13k, 13k+3 or 13k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 5 are greater than 1.at n=37A035951
- Concatenate prevprime(n), n, and nextprime(n).at n=6A049857
- Generating function: 1/((1-x)*(1-x^2)^2*(1-x^3)^3*(1-x^4)^4).at n=21A064349
- Numbers k such that k^5 + 2^k is prime.at n=11A075979
- Starting positions of strings of three 2's in the decimal expansion of Pi.at n=7A083606
- Concatenation of 3 or more numbers in arithmetic progression with positive common difference.at n=43A119426
- Number of divisors d of n! such that d-1 is prime.at n=19A156190
- First of two consecutive numbers with at least one 3 in their prime signature.at n=39A176313
- a(n) = 1 + Sum_{k=1..n} binomial(n,k) * sigma(k).at n=9A222115
- Positive integers m with 2^m*p(m) + 1 prime, where p(.) is the partition function (A000041).at n=24A236390
- Number of compositions of n into parts 3, 5 and 8.at n=47A245369
- Partition of the positive odd integers into minimal blocks such that the concatenation of the numbers in each block is an evil number (A001969). Sequence lists the evil numbers obtained in this way.at n=1A248009
- Given g.f. A(x), let B(x) = 1 + x*A(x)^2 and C(x) = 1 + x*A(x)^3, then B(x*C(x)) = C(x) and C(x/B(x)) = B(x).at n=5A249791
- Numbers n such that the Phi_n(2) is the product of exactly two primes and is divisible by 2n+1.at n=24A250203
- Isolated deficient numbers that are divisible by 3.at n=15A273255
- Compound filter: a(n) = P(A046523(n), A161942(n)), where P(n,k) is sequence A000027 used as a pairing function.at n=35A286034
- Compound filter (prime signature & sum of the divisors): a(n) = P(A046523(n), A000203(n)), where P(n,k) is sequence A000027 used as a pairing function.at n=35A286360