3987
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 5772
- Proper Divisor Sum (Aliquot Sum)
- 1785
- 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
- 2652
- Möbius Function
- 0
- Radical
- 1329
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 51
- 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
- Coordination sequence T6 for Zeolite Code BOG.at n=45A008054
- Coordination sequence T2 for Zeolite Code LOV.at n=42A008135
- Coordination sequence T1 for Zeolite Code MEI.at n=46A008146
- Coordination sequence T2 for Scapolite.at n=40A008263
- Numbers k such that Fib(k) == -34 (mod k).at n=27A023169
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A000201 (lower Wythoff sequence), t = A001950 (upper Wythoff sequence).at n=21A024686
- a(n) = position of n^3 + 9 in A003072.at n=32A024971
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = A000201 (lower Wythoff sequence), t = A001950 (upper Wythoff sequence).at n=20A025119
- Least term in period of continued fraction for sqrt(n) is 7.at n=10A031431
- Composite numbers whose prime factors contain no digits other than 3 and 4.at n=14A036314
- Triangle of coefficients of generating function of 4-ary rooted trees of height at most n.at n=49A036606
- Number of 4-ary rooted trees with n nodes and height at most 4.at n=18A036609
- Numbers whose base-7 representation contains exactly three 4's.at n=34A043411
- Numbers whose base-5 representation contains exactly three 1's and two 2's.at n=27A045231
- Number of nonnegative solutions of x1^2 + x2^2 + ... + x9^2 = n.at n=16A045851
- Number of nonnegative solutions of x1^2 + x2^2 + ... + x9^2 = n.at n=17A045851
- Numbers k such that k and k+1 both have 6 divisors.at n=40A049103
- Consider the Diophantine equation x^3 + y^3 = z^3 + 1 (1 < x < y < z) or 'Fermat near misses'. Arrange solutions by increasing values of z (see A050791). Sequence gives values of x.at n=15A050792
- a(n)=[A*a(n-1)+B*a(n-2)+C]/p^r, where p^r is the highest power of p dividing [A*a(n-1)+B*a(n-2)+C], A=1.0001, B=1.0001, C=1.5, p=2.at n=37A053522
- a(n) = floor( n^Pi ).at n=13A061294