15445
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
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 18540
- Proper Divisor Sum (Aliquot Sum)
- 3095
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12352
- Möbius Function
- 1
- Radical
- 15445
- 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
- 27
- 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 n such that { x +- 2^k : 0 < k < 4 } are primes, where x = 210*n - 105.at n=9A061671
- Expansion of x(1-2x-2x^2)/((1+x)(1-2x)(1-3x)).at n=11A093379
- Triangle read by rows: T(n,k) is the number of Dyck paths with no UUU's and no DDD's, of semilength n having k peak plateaux (0 <= k <= floor(n/3); U=(1,1), D=(1,-1)).at n=45A166285
- Number of Dyck paths with no UUU's and no DDD's, of semilength n having no peak plateaux (U=(1,1), D=(1,-1)).at n=15A166286
- Centered 44-gonal numbers.at n=26A195318
- a(0)=a(1)=0; for n>1, a(n) = numerator( r(n) ), where r(n) = r(n-1)+r(n-2)+A027641(n-2)/A027642(n-2) and r(0)=r(1)=a(0).at n=12A227500
- The 60-degree spoke (or ray) of a hexagonal spiral of Ulam.at n=36A244802
- Number of length n 0..2 arrays with each partial sum starting from the beginning no more than sqrt(3) standard deviations from its mean.at n=8A244934
- T(n,k)=Number of length n 0..k arrays with each partial sum starting from the beginning no more than sqrt(3) standard deviations from its mean.at n=53A244940
- Primitive part of A006190(n), n >= 1.at n=14A253807
- a(n) is the least integer k such that there are n values of i <= k for which gpf(i^2 + 1) = gpf(k^2 + 1), where gpf(x) is the greatest prime factor of x.at n=23A258840
- Binomial transform of double factorial n!! (A006882).at n=9A263529
- Numbers k such that (17*10^k + 43)/3 is prime.at n=18A294228
- Number of partitions of n in which the sequence of the sum of the same summands is increasing.at n=50A304428
- Number of integer partitions of n not containing their mean.at n=36A327472
- Number of pairwise coprime strict compositions of n, where a singleton is always considered coprime.at n=45A337562
- Numbers k such that A339549(k) = A339549(k+1).at n=17A339550
- Truncated centered square numbers: a(n) = 14*n^2 - 22*n + 9.at n=33A389928