13915
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 19152
- Proper Divisor Sum (Aliquot Sum)
- 5237
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9680
- Möbius Function
- 0
- Radical
- 1265
- Omega Function (Ω)
- 4
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 58
- 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
- Centered tetrahedral numbers.at n=27A005894
- Expansion of (1-x^8)*(1+x^5)/(1-x^2)^5.at n=54A027635
- Numerators of continued fraction convergents to sqrt(851).at n=5A042642
- Numbers having four 3's in base 8.at n=7A043436
- Numbers k that divide 7^k + 3^k.at n=24A045586
- Areas of a sequence of right-angled figures described below.at n=18A058195
- Numbers k such that k and k+1 have the same sum of squarefree divisors, or sqf(k) = sqf(k+1), where sqf(k) = A048250(k).at n=8A063964
- a(n) = (6*n+1)*(6*n+7).at n=19A085026
- One seventh of the sum of the first n primes, when an integer.at n=28A112272
- 1A coefficients in an expansion of the elliptic genus of the K3 surface.at n=6A169717
- Records in A087669.at n=32A192230
- Numbers k such that the average of the divisors of k and k+1 is the same.at n=9A238380
- a(n) is the smallest number k such that the symmetric representation of sigma(k) has n parts.at n=10A239663
- a(n) = n*(n + 1)*(7*n + 11)/6.at n=22A255687
- Records in A249860.at n=43A276705
- a(n) = a(n-1) + a(a(n-1) mod n) + 1, a(0) = 1.at n=30A308576
- a(n) = Product_{d|n, d>1} prime(1+(d mod 12)).at n=15A320112
- G.f.: Sum_{k>=1} (k^3 * x^(k^2) / Product_{j=1..k} (1 - x^j)).at n=36A333151
- 1 together with the square array T(n,k) read by upward antidiagonals in which T(n, k), n >= 1, is the n-th odd number j >= 3 such that the symmetric representation of sigma of j has k >= 2 parts.at n=55A346969
- Number k such that A033634(k) = A033634(k+1).at n=9A349224