11818
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18720
- Proper Divisor Sum (Aliquot Sum)
- 6902
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5580
- Möbius Function
- -1
- Radical
- 11818
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 24
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that phi(k + 12) | sigma(k) for k not congruent to 0 (mod 3).at n=40A015850
- Numbers k whose decimal representation, read as a base-12 value and divided by k, yields an integer.at n=11A032555
- a(1) = 1; for n>1, a(n) = a(n-1)*b(n-1) + 1, where {b(k)} is the concatenated list of the ordered positive divisors of the terms of {a(k)}.at n=12A129645
- Concatenated list of the positive divisors of the terms of sequence A129645.at n=59A129646
- Numbers n such that sigma(2*phi(n)) = 2*sigma(n).at n=8A137733
- a(n) = n*(8*n+7).at n=38A139278
- 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, 0), (0, 1, 0), (1, -1, 1), (1, 0, -1)}.at n=9A148413
- a(n) = A205110(n)/n.at n=42A205111
- Numbers consisting of ones and eights.at n=35A213084
- Number of 3 X n 0..1 arrays with rows and antidiagonals unimodal and columns nondecreasing.at n=11A224147
- Number of (7+2) X (n+2) 0..1 arrays with every 3 X 3 subblock sum of the two sums of the diagonal and antidiagonal minus the two minimums of the central column and central row nondecreasing horizontally, vertically and ne-to-sw antidiagonally.at n=9A254913
- Numbers which are divisible by prime(d) for all digits d in their decimal representation.at n=29A256786
- a(n) = number of steps required to reach 0 from F(n+2) by repeatedly subtracting from a natural number the number of ones in its Zeckendorf representation. Here F(n) = the n-th Fibonacci number, F(0) = 0, F(1) = 1, F(2) = 1, F(3) = 2, ...at n=23A261082
- a(0) = 0, a(1) = 1, for n > 1, a(n) = a(n-1) + a(n-A002487(n)).at n=27A283474
- First differences of A283474.at n=32A283479
- Numbers that contain exactly one pair of identical digits x and a triple of identical digits y (x not equal y).at n=36A291312
- Numbers that can be written in more than one way as p^2 + q^3 + r^4 with p, q and r primes.at n=17A318530
- Number of non-isomorphic strict T_0 multiset partitions of weight n.at n=10A319560
- Indices of primes followed by a gap (distance to next larger prime) of 38.at n=28A320717
- Number of integer partitions of n with exactly two distinct multiplicities.at n=40A325243