7939
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8424
- Proper Divisor Sum (Aliquot Sum)
- 485
- 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
- 7456
- Möbius Function
- 1
- Radical
- 7939
- 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
- 145
- 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
- Numbers k such that 9*2^k - 1 is prime.at n=25A002236
- Numerators of continued fraction convergents to sqrt(682).at n=5A042310
- Numerators of continued fraction convergents to sqrt(705).at n=5A042356
- Numbers whose base-4 representation contains exactly three 0's and three 3's.at n=26A045079
- a(1) = 8; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=38A046258
- An approximation to sigma_{5/2}(n): round( sum_{d|n} d^(5/2) ).at n=33A058273
- An approximation to sigma_{5/2}(n): ceiling( sum_{d|n} d^(5/2) ).at n=33A058274
- Integer part of log(n!)^(1 + log(1 + log(1 + n))).at n=20A062445
- Centered 21-gonal numbers.at n=27A069178
- Least m such that sqrt(m) has a period 2n continued fraction expansion whose palindrome part concatenates to a palindromic prime.at n=17A072135
- Numbers k such that the k-th term of the EKG sequence (A064413(k)) has more than one controlling prime.at n=31A073735
- Maximal troughs in decimal expansions of Pi: positions of troughs equal to 8.at n=12A105276
- Numbers n such that P(4n) is prime, where P(m) is the number of partitions of m.at n=28A111045
- Semiprimes of the form 2*n + 1, where n is a square.at n=27A111351
- Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 3X3 tee 1,1 1,2 1,3 2,2 3,2 in any orientation.at n=12A146008
- Numbers such that each digit leaves the same nonzero remainder when each is divided into the number.at n=43A152824
- Number of possible values of C(v) = the number of valid mountain-valley assignments for a flat-foldable origami vertex v of degree 2n.at n=21A156209
- a(n) = 18*n^2 + 1.at n=20A157889
- a(n) = 441*n + 1.at n=17A158322
- Expansion of (1/(1-x)^2)*c(x/(1-x)^4) where c(x) is the g.f. of A000108.at n=6A162477