7191
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
- 12
- Divisor Sum
- 11232
- Proper Divisor Sum (Aliquot Sum)
- 4041
- 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
- 4416
- Möbius Function
- 0
- Radical
- 2397
- Omega Function (Ω)
- 4
- 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
- 70
- 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
- Expansion of 1/((1-2*x)*(1-6*x)*(1-7*x)*(1-12*x)).at n=3A026543
- Multiplicity of highest weight (or singular) vectors associated with character chi_131 of Monster module.at n=38A034519
- Can express a(n) with the digits of a(n)^2 in order, only adding plus signs.at n=46A038206
- Triangle read by rows giving number of arrangements of k dumbbells on 2 X n grid (n >= 0, k >= 0).at n=50A046741
- a(n) = T(0,n) + T(1,n-1) + ... + T(n,0), array T given by A048472.at n=9A048481
- Arrays of dumbbells.at n=5A055608
- a(1) = 1, a(n) = concatenation of two closest factors of a(n-1) whose product equals a(n-1) or if a(n-1) is a prime then the concatenation of 1 and a(n-1).at n=5A062095
- Sixth column of A046741.at n=4A062126
- Numbers k such that k and k+1 have the same sum of unitary divisors (A034448).at n=18A064125
- a(n) = (3/2)*a(n-1) if a(n-1) is even; (3/2)*(a(n-1)+1) if a(n-1) is odd.at n=19A070885
- Partial sums of A038580.at n=14A086749
- Duplicate of A086749.at n=14A086750
- Number of subsets of {1, ..., n} that are not sum-free.at n=13A088809
- Least number beginning with prime(n) such that every concatenation is a prime.at n=19A090508
- a(n) = 25*n^2 - 2*n.at n=16A154376
- Numbers k such that 12*k - 5, 12*k - 1, 12*k + 1, and 12*k + 5 are primes.at n=33A174372
- Number of (n+2)X3 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..3 introduced in row major order.at n=4A204475
- Number of (n+2)X7 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..3 introduced in row major order.at n=0A204480
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..3 introduced in row major order.at n=14A204483
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..3 introduced in row major order.at n=10A204483