8929
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
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8930
- 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
- 8928
- Möbius Function
- -1
- Radical
- 8929
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 96
- 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
- 1110
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes of the form k^2 - k - 1.at n=46A002327
- Convolution of composite numbers and odd numbers.at n=23A023650
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 50 ones.at n=32A031818
- Numbers k such that 249*2^k+1 is prime.at n=41A032501
- Good sequence of increments for Shell sort (best on big values).at n=10A033622
- Denominators of continued fraction convergents to sqrt(138).at n=9A041253
- Primes whose sum of digits is the perfect number 28.at n=21A048517
- First term of weak prime quintets: p(m+1)-p(m) < p(m+2)-p(m+1) < p(m+3)-p(m+2) < p(m+4)-p(m+3).at n=22A054823
- Bond percolation series for square lattice near a wall.at n=19A056532
- Primes p such that x^31 = 2 has no solution mod p.at n=33A059225
- Distinct (non-overlapping) twin Harshad numbers whose sum is prime.at n=35A060288
- Primes which are sums of twin Harshad numbers (includes overlaps).at n=40A060290
- Primes with 11 as smallest positive primitive root.at n=37A061324
- Potential Sierpiński numbers: integers for which the smallest m > 2^10 in A040076 such that n*2^m+1 is prime (A050921).at n=35A064721
- Primes such that prime(p) +- pi(p) are simultaneously prime.at n=20A065117
- Numbers, not composed of the same digits, such that the geometric and arithmetic means of their decimal digits are integers.at n=38A067452
- a(1) = 2; for n > 1, a(n) is the smallest prime > a(n-1) such that each successive digit in the concatenation of terms (that does not follow 9) is greater than the previous digit.at n=9A068827
- Centered 18-gonal numbers.at n=31A069131
- Primes p such that the period of the decimal expansion of 1/p is a square.at n=16A072858
- Numbers k such that there are exactly 8 numbers j for which binomial(k, floor(k/2)) / binomial(k,j) is an integer, i.e., A080383(k) = 8.at n=47A080386