15178
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 22770
- Proper Divisor Sum (Aliquot Sum)
- 7592
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7588
- Möbius Function
- 1
- Radical
- 15178
- 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
- 71
- 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
- Magic numbers: atoms with full shells containing any of these numbers of electrons are considered electronically stable.at n=42A018227
- Numbers k such that the continued fraction for sqrt(k) has period 59.at n=22A020398
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 35.at n=0A031623
- Stirling-like number triangle defined by sequence A000217.at n=32A080248
- a(n) = a(n-1) + 4*a(n-2) for n>1, a(0) = a(1) = 2.at n=10A102446
- Even numbers k such that if a person is born in year k and lives not more than 100 years, then he never celebrates his prime birthday on a prime year.at n=13A124658
- Row sums of triangle A131402.at n=13A131403
- Numerator of A166100(A166101(n))/A166102(n).at n=31A166272
- Number of n X 3 1..2 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 nonincreasing order.at n=42A166830
- Semiprimes that are the sum of 10 consecutive primes.at n=18A185347
- Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=16A192959
- a(n) = number of integers in range [2^(n-1),(2^n)-1] which permutation A209861/A209862 sends to odd-sized orbits.at n=17A209867
- Expansion of 1/((1-x)(1-3x)(1-6x)(1-10x)(1-15x)).at n=3A226941
- Molien series for invariants of finite Coxeter group A_10.at n=54A266779
- Numbers that can be written in more than one way as p^2 + q^3 + r^4 with p, q and r primes.at n=21A318530
- Number T(n,k) of parts in all proper k-times partitions of n into distinct parts; triangle T(n,k), n >= 1, 0 <= k <= max(0,n-2), read by rows.at n=64A327632
- G.f. satisfies A(x) = exp( Sum_{k>=1} A(x^k) * x^k/(k * (1 + 3*x^k)) ).at n=13A363581
- a(1) = 1; for n > 1, a(n) is the smallest unused positive number such that sopfr(|a(n) - a(n-1)|) = sopfr(a(n) + a(n-1)) and Omega(|a(n) - a(n-1)|) = Omega(a(n) + a(n-1)), where sopfr(k) is the sum of the primes dividing k, with repetition.at n=31A370503