15748
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 28672
- Proper Divisor Sum (Aliquot Sum)
- 12924
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7560
- Möbius Function
- 0
- Radical
- 7874
- Omega Function (Ω)
- 4
- 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
- 128
- 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
- a(1) = 2, a(n) = sigma(a(n-1)).at n=12A007497
- Records in A065925.at n=21A065927
- a(n) = (3*n+1)*(3*n+4).at n=41A085001
- a(n) = sigma^n(n), where sigma^n denotes functional iteration.at n=7A090896
- a(n) = sigma^n(n), where sigma^n denotes functional iteration.at n=8A090896
- Number of arrangements of 3 nonzero numbers x(i) in -n..n with the sum of trunc(x(i)/x(i+1)) equal to zero.at n=21A189546
- Sum of the heights of all dispersed Dyck paths of length n (i.e., of Motzkin paths of length n with no (1,0) steps at positive heights).at n=15A191315
- -2-Knödel numbers.at n=27A225506
- Number of length n arrays of permutations of 0..n-1 with each element moved by -6 to 6 places and every three consecutive elements having its maximum within 4 of its minimum.at n=12A263701
- Denominators of triangle related to enumeration of minimal 2-covers of a labeled n-set.at n=24A280753
- Length of longest cycle in n-th row of A329278 (triangular numbers mod 2^n).at n=14A330766