7279
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
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7560
- Proper Divisor Sum (Aliquot Sum)
- 281
- 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
- 7000
- Möbius Function
- 1
- Radical
- 7279
- Omega Function (Ω)
- 2
- 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
- 176
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Number of restricted solid partitions of n.at n=17A002974
- a(n) = 4*a(n-1) + n with n > 1, a(1)=1.at n=6A014825
- Lucky numbers with size of gaps equal to 14 (lower terms).at n=37A031896
- Lucky numbers that are decimal concatenations of n with n + 7.at n=8A032657
- Alternating sum transform (PSumSIGN) of A000975.at n=13A034299
- Moebius transform of A000048 (starting at term 0).at n=18A054174
- Numbers m such that 2^m reversed is prime.at n=26A057708
- a(n) = least natural number k such that f(k) begins a maximal zigzag of length n in the prime gaps function f(x) = p(x+1)-p(x), where p(x) denotes the x-th prime. (Cf. A066485.)at n=17A066918
- Nonprime numbers n such that q=phi(n)/(sigma(n)-n-1) is an integer and n is not a prime square.at n=41A070161
- Expansion of 1/((1-2*x)*(1-x^2)^2).at n=12A091919
- Number of interior balls in a truncated octahedral arrangement.at n=7A093033
- Modulo 2 binomial transform of the Jacobsthal numbers J(n).at n=14A100745
- Reduced numerators of the central moments of the distribution of random line segments picked on a unit line segment.at n=13A103307
- a(n) = A108462(A025487(n)).at n=15A108463
- Numbers with composite sum of digits and prime sum of cubes of digits.at n=35A121642
- Least k such that the Collatz (3x+1) iteration starting with k has "dropping time" A122437(n).at n=48A122442
- T(n,k) = n*T(n,k-1) + k, with T(n,1) = 1, square array read by ascending antidiagonals (n >= 0, k >= 1).at n=61A126885
- a(n) = 3*A131090(n) - A131090(n+1).at n=16A135261
- Composite terms in A143578.at n=40A142591
- Generalized q-Stirling 2nd numbers (see A022166):q=4;m=3; t1(n, k, q_) = (1/(q - 1)^k)*Sum[(-1)^(k - j)*Binomial[k + n, k -j]*q-Binomial[j + n, j, q - 1], {j, 0, k}].at n=29A156825