9813
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13088
- Proper Divisor Sum (Aliquot Sum)
- 3275
- 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
- 6540
- Möbius Function
- 1
- Radical
- 9813
- 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
- 42
- 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=25A031564
- Numbers k such that 201*2^k+1 is prime.at n=15A032477
- Sums of 7 distinct powers of 3.at n=32A038469
- 4n^2+1, 2n^2+1, 2n^2-1 are all prime.at n=27A055755
- a(0) = 1; a(n) = half of the a(n-1)-th even nontotient number.at n=9A071598
- a(0)=1, a(n)=2^n+n^2-2*a(n-1).at n=16A082384
- Start with 1 and repeatedly reverse the digits and add 67 to get the next term.at n=23A118214
- Smallest number k such that k^n is equal to the sum of n consecutive primes, or 1 if it does not exist.at n=40A123112
- Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n and having height k (1 <= k <= n).at n=39A129161
- Integers k such that 10^k+37 is a prime number.at n=23A135109
- Number of partitions of n into parts with no prime gaps in their factorization.at n=33A137792
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, 1), (1, 0, -1), (1, 0, 0), (1, 1, -1)}.at n=9A148418
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (1, -1, 1), (1, 0, -1), (1, 1, 0)}.at n=8A149274
- a(n) + a(n+1) + a(n+2) = n^5, with a(1) = a(2) = 0.at n=8A152730
- n^3+Largest square, (Largest square <= n^3).at n=17A176580
- Number of partitions of n for which (number of occurrences of the least part) = (number of occurrences of greatest part).at n=41A236543
- An oscillating sequence: a(n) = n^2 + 2^(n-1) - 2*a(n-1), n>0, with a(1) = 1.at n=16A238315
- The bisection of A238315 that remains constant with changes in the offset of the exponent of the second term.at n=8A239367
- Partial sums of A252750: a(0) = 0; for >= 1: a(n) = A252750(n) + a(n-1).at n=59A252751
- Triangle read by rows: T(n,k) = number of unlabeled graphs with n nodes and connectivity exactly k (n>=1, 0<=k<=n-1).at n=62A259862