7945
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
- 10944
- Proper Divisor Sum (Aliquot Sum)
- 2999
- 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
- 5424
- Möbius Function
- -1
- Radical
- 7945
- 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
- 127
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n*(13*n - 1)/2.at n=35A022270
- Expansion of 1/((1-5x)(1-6x)(1-8x)(1-10x)).at n=3A028171
- Numbers m such that the factorizations of m..m+3 have the same number of primes (including multiplicities).at n=36A045940
- Numbers k such that 6*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=16A056717
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 71 ).at n=38A063344
- a(n) = n*(n-1)*(n^2 + 2)/6.at n=15A071244
- Non-balanced numbers in A015765.at n=33A074868
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=4A098936
- A "cosh transform" of binomial(2n,n-1).at n=7A106391
- Numbers n such that n, n+1, n+2 and n+3 are products of exactly 3 primes.at n=34A124057
- Prime numbers concatenated with 45.at n=21A137521
- Products of 3 distinct safe primes.at n=20A157354
- Number of nX3 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or one horizontal or vertical neighbors.at n=3A199352
- Number of nX4 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or one horizontal or vertical neighbors.at n=2A199353
- T(n,k)=Number of nXk 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or one horizontal or vertical neighbors.at n=17A199356
- T(n,k)=Number of nXk 0..3 arrays with values 0..3 introduced in row major order, the number of instances of each value within one of each other, and every element equal to zero or one horizontal or vertical neighbors.at n=18A199356
- The number of ways to color the vertices of all (11) simple unlabeled graphs on 4 nodes using at most n colors.at n=6A199394
- Second elementary symmetric function of the first n terms of (2,2,3,3,4,4,5,5...).at n=18A203299
- Triangle read by rows, T(n,k) n>=0, k>=0, generalization of A000255.at n=32A216154
- Minimum value unattainable as the sum of 2 attained values of a*b+a*c+b*c with a,b,c 0..n integers.at n=38A225272