15384
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 38520
- Proper Divisor Sum (Aliquot Sum)
- 23136
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5120
- Möbius Function
- 0
- Radical
- 3846
- Omega Function (Ω)
- 5
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 53
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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 the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 31.at n=40A031529
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 31.at n=3A031709
- Least positive k such that k * [RSA-640]^n - 1 is prime, where RSA-640 is the 193 decimal digit RSA challenge number A391940(14).at n=42A108573
- Numbers k such that k and 5*k, taken together, are pandigital.at n=6A115925
- a(n) = 8*a(n-1) - 6*a(n-2), a(0)=1, a(1)=6.at n=5A147838
- Number of terms with n digits in A154780.at n=20A154779
- a(n) = 961*n^2 + 2*n.at n=3A158413
- Number of ways to place 4 nonattacking knights on a 4 X n board.at n=7A172213
- Monotonic ordering of nonnegative differences 2^i-10^j, for 40>= i>=0, j>=0.at n=36A192124
- Monotonic ordering of nonnegative differences 4^i-10^j, for 40>=i>=0, j>=0.at n=18A192171
- Number of subsets of {1..n} (including empty set) such that the pairwise LCMs of elements are all distinct.at n=18A196721
- Number of (n+1)X(4+1) 0..3 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with values 0..3 introduced in row major order.at n=4A231359
- Number of (n+1)X(5+1) 0..3 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with values 0..3 introduced in row major order.at n=3A231360
- T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with values 0..3 introduced in row major order.at n=31A231363
- T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with no element unequal to a strict majority of its horizontal, vertical and antidiagonal neighbors, with values 0..3 introduced in row major order.at n=32A231363
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 123", based on the 5-celled von Neumann neighborhood.at n=27A270212
- Number of nX3 0..1 arrays with every element unequal to 0, 1, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=13A318540
- Colombian numbers that are also Bogotá numbers.at n=37A336984
- Number of integer partitions of the n-th semiprime into semiprimes.at n=38A338902
- Smallest b > 1 such that b^(p-1) == 1 (mod p^4) for p = prime(n).at n=19A353937