15927
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 21240
- Proper Divisor Sum (Aliquot Sum)
- 5313
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10616
- Möbius Function
- 1
- Radical
- 15927
- 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
- 252
- 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
- a(0) = 1, a(n) = 13*n^2 + 2 for n>0.at n=35A010004
- Smallest positive integer m such that m = pi(n*m) = A000720(n*m).at n=9A038626
- Numbers whose base-5 representation contains exactly three 0's and three 2's.at n=12A045187
- Least k such that gcd(prime(k+1)-1, prime(k)-1) = 2n.at n=34A067605
- Values of transition of A072608(n) from alternating behavior (0,1,0,1,..) into steadily-1 (1,1,1,..) behavior or changing back. Expressing in terms of A072609(n): at n values it switches from steadily 0 into steadily 1 successive values or back.at n=15A072610
- Numbers k such that 4^k + 3 is prime.at n=24A089437
- a(n) is the largest number m such that m = pi(n*m).at n=9A102281
- Numbers k such that the difference between k-th prime and next prime is 70.at n=1A116493
- Number of n-bead necklaces labeled with numbers -1..1 not allowing reversal, with sum zero and first differences in -1..1.at n=16A208986
- a(n) = smallest m such that A031131(m) = 2*n.at n=42A261525
- Partial sums of A299279.at n=18A299280
- Triangle defined by T(n,k) = Sum_{j>=0} C(j+k, k) * C((j+k)*k, n-k) / 2^(j+k+1), for n>=0, k = 0..n, as read by rows.at n=31A300280
- Numbers k such that floor(prime(k)/k) < floor(prime(k+1)/(k+1)).at n=15A308082
- The index of prime(n) in A337182.at n=26A338222
- Number of solutions to +-2 +- 3 +- 5 +- 7 +- ... +- prime(n-1) = n.at n=23A350695
- Position of second appearance of 2n in the sequence of prime gaps A001223; if 2n does not appear at least twice, a(n) = -1.at n=34A356221