7307
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7308
- 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
- 7306
- Möbius Function
- -1
- Radical
- 7307
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 44
- 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
- 931
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of acyclic ethylene derivatives with n carbon atoms.at n=10A005959
- Where the prime race among 5k+1, ..., 5k+4 changes leader.at n=42A007353
- a(n) = floor(2nd elementary symmetric function of Sum_{j=1..k} 1/j, k = 1,2,...,n).at n=35A025212
- a(n) = (d(n)-r(n))/2, where d = A026046 and r is the periodic sequence with fundamental period (0,1,0,1).at n=31A026047
- 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=6A031583
- Table read by rows: T(n,k) = number of 2-connected planar graphs with n >= 1 nodes and 0 <= k <= 3n-6 edges.at n=87A049336
- Prime number spiral (clockwise, Southwest spoke).at n=15A054568
- Fourth term of strong prime quintets: p(m-2)-p(m-3) > p(m-1)-p(m-2) > p(m)-p(m-1) > p(m+1)-p(m).at n=19A054811
- Discriminants of imaginary quadratic fields with class number 25 (negated).at n=11A056987
- Primes starting and ending with 7.at n=14A062334
- a(1) = 1; for n>1, a(n) = smallest prime > a(n-1) such that a(1)*...*a(n) + 2 is a prime.at n=42A085013
- Smallest member of a pair of consecutive twin prime pairs that have one prime between them.at n=32A089629
- a(1)=11; for n>1, a(n) is the smallest prime not occurring earlier beginning with a(n-1) without its first digit. Single-digit primes are not allowed unless they arise from the previous term as multi-digit number with leading zero(s) (i.e., a(n-1) has 0 as second digit) which are remembered for the subsequent left-truncations.at n=43A089755
- a(0)=1; a(n) = sigma_1(n) + sigma_2(n) + sigma_3(n).at n=18A092347
- Primes p = prime(k) such that both p+2 and prime(k+4)-2 are prime numbers.at n=33A105411
- Primes p = prime(k) such that both p+2 and prime(k+6)-2 are prime numbers.at n=25A105413
- a(n) = A007290(n+2) - 1 = 2*C(n+2,3) - 1.at n=27A108766
- Primes prime(i) such that their sum-of-index-digits A007953(i) and their sum-of-digits A007605(i) are consecutive primes.at n=36A117460
- a(n) = prime(n^2 + n + 1).at n=30A122566
- Prime sums of 5 positive 5th powers.at n=19A123034