9887
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 9888
- 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
- 9886
- Möbius Function
- -1
- Radical
- 9887
- 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
- 241
- 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
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1220
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes that remain prime through 3 iterations of function f(x) = 10x + 3.at n=28A023300
- 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 99.at n=8A031597
- Sum of digits = 8 times number of digits.at n=42A061425
- a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 1.at n=27A061511
- Primes in which neighboring digits differ at most by 1.at n=39A068148
- Primes with either no internal digits or all internal digits are 8.at n=48A069683
- A 2nd order recursion: a(1)=a(2)=1; a(n) = prime(a(n-2)+a(n-1)) = A000040(a(n-2)+a(n-1)).at n=7A082096
- a(n) = largest prime using least number of possible digits with a digit sum n, or 0 if no such number exists. E.g., if n > 9 and there are no two-digit primes with a given digit sum n then three-digit numbers are explored and so on.at n=31A088115
- Numbers which are primes and which remain prime for three successive applications of incrementing each digit by 2 with carries ignored.at n=16A088787
- Smallest number not occurring earlier fitting the repeating pattern "99887766554433221100".at n=40A098782
- Primes from merging of 4 successive digits in decimal expansion of the Golden Ratio, (1+sqrt(5))/2.at n=0A103810
- Primes from merging of 4 successive digits in decimal expansion of the Golden Ratio, (1+sqrt(5))/2.at n=30A103810
- Primes which are 1 + strobogrammatic numbers A000787(n): the same upside down.at n=8A105268
- Primes with minimal digit = 7.at n=15A106107
- Primes having only {7, 8, 9} as digits.at n=17A106110
- Primes having only {6, 7, 8, 9} as digits.at n=45A106111
- Primes with digit sum = 32.at n=4A106768
- a(n) = (1/3)*n^3 - n^2 - (1/3)*n - 1.at n=32A109620
- Sum of the squares of the first n squarefree numbers.at n=23A111715
- Row sums of triangle A114176, where the g.f. of column n equals the g.f. of row n divided by (1-x)^(n+1)*(1-x^2)^n.at n=9A114177