7137
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 11284
- Proper Divisor Sum (Aliquot Sum)
- 4147
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 2379
- 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
- 49
- 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
- Numbers k that divide s(k), where s(1)=1, s(j)=13*s(j-1)+j.at n=24A014861
- Numbers k such that k-th and (k+1)-st term of A038593 differ by 3.at n=13A038634
- The sequence e when b=[ 1,0,1,1,1,... ].at n=35A042953
- Numbers n such that 81*2^n-1 is prime.at n=17A050566
- Sum of divisors of twice square numbers.at n=38A065765
- Numbers k such that (1/k) * Sum_{d|k} d*sigma(d) is an integer.at n=6A069520
- Numbers k that divide 2^(k+3) - 1.at n=33A069927
- Expansion of 1/(1-x+2*x^2-x^3) in powers of x.at n=32A077954
- Expansion of 1/(1+x+2*x^2+x^3).at n=32A077979
- a(1) = 1, otherwise a(n) = floor(e^(n+1)/(e^2 + 1)).at n=10A090039
- a(n) is the least positive integer such that nextprime(a(n)^n) - prevprime(a(n)^n) = 4.at n=33A090125
- After the first two terms, each subsequent term is the smallest integer that is an outlier of the previous dataset, based on the criterion of 3 sample standard deviations above the mean.at n=37A103231
- Numbers k such that k concatenated with k+3 gives the product of two numbers which differ by 7.at n=0A116180
- Start with 1 and repeatedly reverse the digits and add 53 to get the next term.at n=46A118150
- Multiples of 13 containing a 13 in their decimal representation.at n=20A121033
- a(n) = c is least number such that 10^n/2 -/+ c are primes.at n=45A124049
- Numbers which are the sum of 3 cubes of distinct odd primes.at n=17A138853
- Numbers which are the sum of three cubes of distinct primes.at n=34A138854
- a(n) = prime(n^2) - n^2.at n=31A141129
- a(n) = Sum_{k=0..n} (-1)^k * binomial(n, k) * A000931(n-k+4).at n=17A144413