15397
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15660
- Proper Divisor Sum (Aliquot Sum)
- 263
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15136
- Möbius Function
- 1
- Radical
- 15397
- 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
- 133
- 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
- a(n) = 2^n - Fibonacci(n+2).at n=14A008466
- a(n) = Sum_{i=0..n} Sum_{j=0..n} T(i,j), T given by A026780.at n=11A026789
- Lucky numbers with size of gaps equal to 20 (lower terms).at n=34A031902
- A Catalan-like sequence.at n=10A054542
- (n - phi(n)) | sigma(n) for composite n not congruent to 2 (mod 4).at n=27A055164
- Semiprimes in A103374.at n=19A103394
- Triangle T(n,k), n>=2, 0<=k<=n-2, read by rows: numbers of binary words of length n containing at least one subword 10^{k}1 and no subwords 10^{i}1 with i<k.at n=78A143291
- Positive numbers y such that y^2 is of the form x^2+(x+577)^2 with integer x.at n=6A159626
- Number of 0..n arrays x(0..10) of 11 elements with zero 5th differences.at n=45A200373
- Number of 5-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.at n=8A209117
- Number of (4+2) X (n+2) 0..3 arrays with every consecutive three elements in every row and diagonal having exactly two distinct values, and in every column and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=27A252723
- Number of set partitions of [n] into m blocks such that at least one pair of distinct cyclically consecutive blocks (b,c) = (b,(b mod m)+1) exists having no pair of numbers (i,j) = (i,(i mod n)+1) with i member of b and j member of c.at n=9A271273
- Numbers m such that psi(x) = phi(m) has a solution while sigma(y) = phi(m) has none.at n=16A291524
- Composite hypotenuses of primitive Pythagorean triangles (A120961) that are not circumdiameters of non-Pythagorean primitive Heronian triangles (A285579).at n=18A329148
- Numbers that are the sum of eight fourth powers in seven or more ways.at n=37A345582
- Numbers that are the sum of eight fourth powers in exactly seven ways.at n=34A345839