7931
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9984
- Proper Divisor Sum (Aliquot Sum)
- 2053
- 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
- 6120
- Möbius Function
- -1
- Radical
- 7931
- 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
- 75
- 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 + n*(n-1)*(n-2)*(n-3).at n=11A001094
- Heptagonal (or 7-gonal) pyramidal numbers: a(n) = n*(n+1)*(5*n-2)/6.at n=21A002413
- Maximal sum of inverse squares of the singular values of triangular anti-Hadamard matrices of order n.at n=10A005313
- Sum of squares of first n positive integers congruent to 1 mod 3.at n=13A024215
- a(1) = 3; a(n+1) = a(n)-th nonprime, where nonprimes begin at 1.at n=32A025004
- a(1) = 5; a(n+1) = a(n)-th nonprime, where nonprimes begin at 4.at n=30A025010
- Character of extremal vertex operator algebra of rank 11.at n=4A028531
- Position of rightmost 0 in 2^n increases.at n=14A031140
- Position of rightmost 0 (including leading 0) in 2^n increases.at n=25A031142
- a(n) = (3*n - 1)*(4*n - 1).at n=26A033578
- Numbers whose base-4 representation contains exactly two 2's and four 3's.at n=22A045147
- Reversion of y - y^2 - y^5.at n=10A063021
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=2A098936
- Structured disdyakis dodecahedral numbers (vertex structure 9).at n=10A100161
- Numbers k such that k^6+6 is prime.at n=36A109836
- Numbers k such that the numerator of the Bernoulli number B(2k) ends with the digits 691.at n=29A132184
- Numbers such that the digital sums in bases 2, 3, 5 and 7 all are equal.at n=12A135127
- Expansion of 1/(x^k*(1-x-2*x^(k+1))) for k=9.at n=35A143452
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 11000-01111-11000 pattern in any orientation.at n=11A147459
- Number of symmetry classes of 3 X 3 magilatin squares with positive values and magic sum n.at n=43A173730