4987
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
- 2
- Divisor Sum
- 4988
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 4986
- Möbius Function
- -1
- Radical
- 4987
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 165
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 667
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = floor(3^n / 2^n).at n=21A002379
- Number of bipartite partitions of n white objects and 7 black ones.at n=8A002756
- Number of bipartite partitions of n white objects and 8 black ones.at n=7A002757
- Primes of form n^2 + n + 17.at n=46A007635
- Coordination sequence T4 for Zeolite Code MFI.at n=45A008167
- Coordination sequence T7 for Zeolite Code MFI.at n=45A008170
- [ sqrt(3/2)^n ].at n=42A014215
- Numbers k such that the continued fraction for sqrt(k) has period 66.at n=15A020405
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A000201 (lower Wythoff sequence).at n=27A024685
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = A000201 (lower Wythoff sequence).at n=26A025118
- Numbers having period-4 6-digitized sequences.at n=23A031197
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 69.at n=21A031567
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 40 ones.at n=15A031808
- Upper prime of a difference of 14 between consecutive primes.at n=27A031933
- Numbers whose base-5 representation contains exactly three 2's and two 4's.at n=15A045291
- Discriminants of imaginary quadratic fields with class number 9 (negated).at n=23A046006
- Smallest of three consecutive primes with a difference of 6: primes p such that p+6 and p+12 are the next two primes.at n=34A047948
- Primes whose sum of digits is the perfect number 28.at n=4A048517
- Numbers k such that 135*2^k-1 is prime.at n=21A050593
- Primes p from A031924 such that A052180(primepi(p)) = 7.at n=26A052231