15561
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
- 24
- Divisor Sum
- 29120
- Proper Divisor Sum (Aliquot Sum)
- 13559
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7776
- Möbius Function
- 0
- Radical
- 5187
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 84
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = 5^n - 2^n.at n=6A005057
- Related to sextic factorial numbers A008542.at n=3A034789
- Gaps of 7 in sequence A038593 (lower terms).at n=36A038653
- Numbers k such that sopfr(k) = sopfr(k + sopfr(k)).at n=22A050780
- Numbers whose 4th power can be expressed as the sum of two positive cubes in more than one way.at n=9A051388
- Product of all distinct nonzero numbers that can be formed from the digits of n.at n=18A061497
- a(n) = T(n) concatenated with reverse(T(n)) divided by 11, where T(n) is the n-th triangular number.at n=18A084008
- A convolution triangle of numbers obtained from A034789.at n=6A092083
- Numbers which are the sum of two positive cubes and divisible by 19.at n=38A102619
- a(n) = binomial(n+2,2) * binomial(n+7,2).at n=12A104676
- Multiples of 1729, the Hardy-Ramanujan number.at n=9A138129
- Half-sum (or average) of cubes of two distinct odd primes.at n=37A138855
- Long legs of primitive Pythagorean triples (a,b,c) for which 2a+1, 2b+1 and 2c+1 are primes.at n=39A165237
- Number of nX2 1..3 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in increasing order.at n=18A166814
- Numbers k whose sum of digits equals the period of 1/k.at n=35A178495
- Odd long legs `B` of more than one primitive Pythagorean triangle.at n=25A179271
- Numbers that are 4-digit palindromes in at least 2 bases.at n=19A180453
- Difference of two positive 6th powers.at n=9A181125
- Numbers n with property that n and 2n are sums of two distinct positive cubes.at n=7A191345
- Integers n such that each of n, 2n and 3n is a sum of 2 distinct positive cubes.at n=1A191383