7987
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 31
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 9348
- Proper Divisor Sum (Aliquot Sum)
- 1361
- 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
- 6804
- Möbius Function
- 0
- Radical
- 1141
- Omega Function (Ω)
- 3
- 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
- 52
- 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
- Sum{T(n-k,k)}, 0<=k<=[ n/2 ], where T is the array in A026386.at n=16A026397
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 11 ones.at n=17A031779
- Numbers whose base-4 representation contains exactly two 0's and four 3's.at n=20A045075
- Array T(n,k) = number of conjugacy classes of subgroups of index k in free group of rank n, read by antidiagonals.at n=30A057004
- Number of conjugacy classes of subgroups of index 3 in free group of rank n.at n=5A057009
- Coefficients in the series (1 + x^2 + x^3 + x^5 + x^7 + x^11 + x^13 + ... )/(1 - x - x^4 - x^6 - x^8 - x^9 - x^10 - x^12 - x^14 - ... ).at n=22A058355
- Triangle read by rows: T(n,k), n >=1, 0 <= k <= C(n,k), = number of n X n symmetric positive definite matrices with 2's on the main diagonal and 1's and 0's elsewhere and with k 1's above the diagonal.at n=56A080858
- Indices of primes in the sequence defined by A(0) = 67, A(n) = 10*A(n-1) - 53 for n > 0.at n=8A101520
- a(n) = reverse(2^n) mod 2^n.at n=16A103166
- Start with 1015 and repeatedly reverse the digits and add 4 to get the next term.at n=87A117807
- Start with 1027 and repeatedly reverse the digits and add 16 to get the next term.at n=21A119455
- Indices of 4's in A090822.at n=35A157107
- a(n) = 242*n + 1.at n=32A157958
- a(n) = 66*n^2 + 1.at n=11A158689
- Column 6 of array in A057004.at n=2A160871
- a(n) = 6n^3 + 1, solution z in Diophantine equation x^3 + y^3 = z^3 - 2. It may be considered a Fermat near miss by 2.at n=10A163827
- The initial decimal digits of 2^a(n) are the decimal digits of n followed by n.at n=20A171652
- The Matula-Goebel numbers of the rooted trees that have palindromic Wiener polynomials.at n=16A198322
- Numbers having exactly three representations by the quadratic form x^2+xy+y^2 with 0<=x<=y.at n=40A198774
- a(n) = 6*11^n + 1.at n=3A199756