7198
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11160
- Proper Divisor Sum (Aliquot Sum)
- 3962
- 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
- 3480
- Möbius Function
- -1
- Radical
- 7198
- Omega Function (Ω)
- 3
- 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
- 70
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Triangle read by rows: T(n,k) = number of permutations of length n with exactly k rising or falling successions, for n >= 1, 0 <= k <= n-1.at n=31A001100
- a(n) = floor( binomial(n,7)/7 ).at n=19A011853
- a(n) = floor(n*(n-1)*(n-2)/30).at n=61A011912
- Numbers k such that the continued fraction for sqrt(k) has period 66.at n=33A020405
- a(n) = position of n^3 + (n+1)^3 + (n+2)^3 in A003072.at n=26A024972
- Numbers having three 7's in base 9.at n=32A043483
- Numbers k such that 195*2^k-1 is prime.at n=47A050849
- Expansion of Product_{k>=1} (1+x^k)^A001055(k).at n=35A066806
- a(n) = 2*prime(n)*prime(n+1).at n=16A069486
- Numbers n such that sum of distinct primes dividing n is divisible by the largest prime dividing n. Also n is neither a prime, nor a true power of prime and n is squarefree. Squarefree solutions of A071140.at n=9A071141
- Numbers of the form 2*p*q where (p,q) is a twin prime pair.at n=6A071142
- Squarefree numbers k such that the largest prime factor of k is equal to the sum of the other prime factors of k.at n=9A071312
- Numbers k such that S(k+2) = d(k)+2, where S(k) is the Kempner function (A002034) and d(k) is the number of divisors of k (A000005).at n=36A073535
- Numbers n such that A076341(n)=0.at n=39A076351
- Squarefree numbers k such that A076341(k) = 0.at n=10A076352
- a(n) = lpf(n) * lpf(n+1) * lpf(n+2), where lpf(n) = A020639(n) is the least prime factor of n.at n=58A079390
- Numbers k such that the sum of primes dividing k (with repetition) / smallest prime dividing k = largest prime dividing k.at n=40A085702
- Number of permutations of length n with exactly 3 rising or falling successions.at n=8A086854
- Numbers k such that numerator of Bernoulli(2*k) is divisible by 37 and 59, the first two irregular primes.at n=29A092231
- a(n) = floor(n*(n^3-n-3)/(2*(n-1))).at n=22A117561