7547
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7548
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 7546
- Möbius Function
- -1
- Radical
- 7547
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 114
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 957
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes.at n=21A000127
- Numbers k such that the continued fraction for sqrt(k) has period 66.at n=35A020405
- Primes that remain prime through 2 iterations of function f(x) = 8x + 7.at n=43A023263
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 85.at n=29A031583
- a(n) = Sum_{i=0..4} binomial(Fibonacci(n),i).at n=8A032439
- a(1) = 2; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=47A033679
- Start of a string of exactly 2 consecutive (but disjoint) pairs of twin primes.at n=20A035790
- Discriminants of imaginary quadratic fields with class number 15 (negated).at n=30A046012
- Let (p1,p2), (p3,p4) be pairs of twin primes with p1*p2=p3+p4-1; sequence gives values of p1.at n=14A047976
- First of four consecutive primes that comprise two sets of twin primes.at n=32A053778
- Numbers k such that 4^k - 3^k is prime.at n=15A059801
- Primes starting and ending with 7.at n=22A062334
- Primes p for which the exponent of the highest power of 2 dividing p! is equal to prevprime(prevprime(p)).at n=32A064396
- Lowest primes in twin packs.at n=26A069457
- Numbers k such that Cyclotomic(k,k) (i.e., the value of k-th cyclotomic polynomial at k) is a prime number.at n=24A070519
- Define the composite field of a prime q to be f(q) = (t,s) if p, q, r are three consecutive primes and q-p = t and r-q = s. This is a sequence of primes q with field (6,2).at n=40A073651
- Near twin primes of order 12: twin primes p,p+2 such that p+12 and p+14 are primes.at n=31A079292
- Numbers k such that (k^k-1)/(k-1) is prime.at n=4A088790
- Smallest member of a pair of consecutive twin prime pairs that have no primes between them.at n=33A089628
- Sum of primes <= p is even and sum is twice a prime.at n=38A089894