15658
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
- 4
- Divisor Sum
- 23490
- Proper Divisor Sum (Aliquot Sum)
- 7832
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7828
- Möbius Function
- 1
- Radical
- 15658
- 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
- 53
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 10.at n=20A031423
- Numbers whose base-5 representation contains exactly three 0's and three 1's.at n=11A045172
- Numbers k such that 231*2^k-1 is prime.at n=45A050867
- a(n) = T(n,n-5), array T as in A055801.at n=35A055805
- a(n) = a(n-1) + a(n - 1 minus the number of terms of a(k) == (mod 6) so far).at n=28A060733
- Number of semiprimes <= 2^n.at n=15A125527
- Number of permutations of length n which avoid the patterns 321 and 1324.at n=18A179257
- a(n) = A001209(n) + 1.at n=32A196069
- Number of 7-bead necklaces labeled with numbers -n..n allowing reversal, with sum zero and first and second differences in -n..n.at n=7A208974
- a(n+3) = 2*a(n+2) + a(n+1) + a(n) with a(0)=0, a(1)=6, a(2)=8.at n=10A276226
- Numbers k such that (44*10^k - 161)/9 is prime.at n=17A295824
- Partial sums of A301692.at n=96A301693
- Number of binary words of length n such that in every prefix and in every suffix the difference between the number of 1's and the number of 0's is in the interval [-2,3].at n=17A306306
- Semiprimes that are the sum of two successive semiprimes and also the sum of three successive semiprimes.at n=42A370162
- Number of Dyck paths of semilength n with strongly unimodal peak heights such that neighboring peaks differ in height by exactly one and first and last peak are at height one.at n=27A371926