7242
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 15552
- Proper Divisor Sum (Aliquot Sum)
- 8310
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2240
- Möbius Function
- 1
- Radical
- 7242
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 70
- 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
- Number of permutations that are 2 "block reversals" away from 12...n.at n=12A007972
- Least term in period of continued fraction for sqrt(n) is 10.at n=17A031434
- Number of certain stackings of n+1 squares on a double staircase.at n=15A055244
- Least positive integer multiples of angle x such that their direction cosines form a unit vector: Sum_{k>0} cos(a(k)*x)^2 = 1, where a(1)=1, a(n+1)>a(n) and x=5/4.at n=37A080198
- Number n-cyclic graphs.at n=11A081809
- a(0)=1; a(n) = sigma_1(n) + sigma_2(n) + sigma_3(n).at n=19A092347
- Values of k such that floor(k*tanh(Pi)) = floor((k+1) tanh(Pi)).at n=26A096613
- Number of products of distinct factorials not exceeding n!.at n=32A101977
- Numbers k such that k * (10^k - 1) + 1 is prime.at n=6A109137
- a(n) = Sum_{k=1..n} k*(prime(k) - k).at n=16A110477
- Next term is the sum of previous term and the square of the sum of its decimal digits, with a(0) = 10.at n=25A112787
- Cascadence of (1+x)^3; a triangle, read by rows of 3n+1 terms, that retains its original form upon convolving each row with [1,3,3,1] and then letting excess terms spill over from each row into the initial positions of the next row such that only 3n+1 terms remain in row n for n>=0.at n=39A120919
- Numbers k such that k and k^2 use only the digits 2, 4, 5, 6 and 7.at n=33A137094
- Let A(0) = 1, B(0) = 0 and C(0) = 0. Let B(n+1) = Sum_{k = 0..n} binomial(n,k)* A(k), C(n+1) = Sum_{k = 0..n} binomial(n,k)*B(k) and A(n+1) = Sum_{k = 0..n} binomial(n,k)*C(k). This entry gives the sequence C(n).at n=9A143817
- 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, 0, 0), (0, -1, 0), (0, 0, -1), (0, 0, 1), (1, 1, 0)}.at n=7A150471
- 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, -1, 0), (-1, 0, -1), (1, 0, 1), (1, 1, 1)}.at n=7A150675
- a(n) = 289*n^2 + 17.at n=5A158585
- a(n) = 25*n^2 + n.at n=16A173089
- Sum of lengths of initial and final horizontal segments over all dispersed Dyck paths of semilength n (i.e., over all Motzkin paths of length n with no (1,0)-steps at positive heights).at n=14A191531
- Number of 2 X 2 matrices with all elements in {1,2,...,n} and determinant in {-1,0,1}.at n=34A209994