15138
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 33969
- Proper Divisor Sum (Aliquot Sum)
- 18831
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4872
- Möbius Function
- 0
- Radical
- 174
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 133
- 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(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (Lucas numbers), t = A023533.at n=38A024476
- Collatz-2 (A063041) trajectory starting at 29.at n=11A063044
- Collatz-2 (A063041) trajectory starting at 29.at n=26A063044
- Collatz-2 (A063041) trajectory starting at 29.at n=41A063044
- Numbers k such that the k-th difference between 2 successive primes equals the squarefree part of k.at n=24A078691
- Even refactorable numbers k such that the number r of odd divisors of k and the number s of even divisors of k are both odd divisors of k.at n=14A120361
- Averages of twin primes of the form : i^2+j^2, as sum of two squares.at n=27A143793
- Numbers k such that k/A000005(k) is a square.at n=40A145450
- Averages of twin prime pairs k such that k*2 and k/2 are squares.at n=7A154670
- Non-deficient numbers with odd sigma such that the sum of the even divisors is twice the sum of the odd divisors.at n=17A171642
- a(n) = 18*n^2.at n=29A195321
- Number of isomorphism classes of nanocones with 3 pentagons and a nearsymmetric boundary of length n.at n=34A198014
- Numbers m with m - 1, m + 1 and q(m) + 1 all prime, where q(.) is the strict partition function (A000009).at n=19A235344
- Number of length 3 1..(n+2) arrays with no leading partial sum equal to a prime.at n=31A254541
- Numbers m with m-1, m+1 and prime(m)+2 all prime.at n=30A259539
- Numbers k such that k and k^2 are the sums of two nonzero squares in exactly two ways.at n=30A273293
- Numbers with at least three digits and with the property that the sum of the cubes of the first and last digit equals the number obtained when the first and last digits are deleted.at n=32A275343
- Numbers n such that the sum of the divisors of n divides sum of squares of divisors of n and number of divisors of n divides n.at n=35A280353
- Sum of all the parts in the partitions of n into 7 parts.at n=29A308926
- Positions k where A348733(k) is not multiplicative.at n=13A348740