9903
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13208
- Proper Divisor Sum (Aliquot Sum)
- 3305
- 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
- 6600
- Möbius Function
- 1
- Radical
- 9903
- Omega Function (Ω)
- 2
- 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
- 73
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- 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 66.at n=28A031564
- Numbers k such that 195*2^k-1 is prime.at n=50A050849
- Treated as strings, n begins with Floor(sqrt(n)).at n=26A069086
- a(n)= 3*a(n-3) +3*a(n-6) +a(n-9).at n=20A109528
- Number of partitions of n in which each part, with the possible exception of the largest, occurs at least twice.at n=43A116931
- Start with 1015 and repeatedly reverse the digits and add 4 to get the next term.at n=44A117807
- Partial sums of near-repdigit primes A056710.at n=22A172983
- a(n) = number of 7-digit primes with digit sum n, where n runs through the non-multiples of 3 in the range [2..62].at n=29A178876
- Numbers k such that (7*10^(2k+1) - 18*10^k - 7)/9 is prime.at n=11A183180
- Number of partitions of n containing a clique of size 10.at n=41A183567
- Semiprimes p such that next semiprime after p is p + 10.at n=37A217030
- Expansion of psi(x^4) / phi(-x^3) in powers of x where phi(), psi() are Ramanujan theta functions.at n=60A261877
- Expansion of psi(-x^3) / f(-x) in powers of x where psi(), f() are Ramanujan theta functions.at n=40A271593
- The number of unitary untouchable numbers <= 10^n.at n=5A290240
- Sum of the largest parts in the partitions of n into 8 parts.at n=32A308998
- a(n) = Sum_{k=1..n} floor(n/k) * 3^(k-1).at n=8A344814
- Numbers k >= 3 such that 1/d(k - 2) + 1/d(k - 1) + 1/d(k) is an integer, d(i) = A000005(i).at n=49A359056