7517
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7518
- 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
- 7516
- Möbius Function
- -1
- Radical
- 7517
- 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
- 88
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 952
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that 2*10^k - 1 is prime.at n=22A002957
- Palindromic primes in base 4.at n=26A029972
- Primes that are palindromic in base 6.at n=29A029974
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 15.at n=4A031603
- Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 4 (mod 5).at n=46A035568
- a(n) = T(2n-1,n), array T given by A048225.at n=46A048234
- Primes for which only two iterations of 'Prime plus its digit sum equals a prime' are possible.at n=37A048524
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 13.at n=24A050962
- a(n) is the first prime p from A031924 such that A052180(primepi(p)) = prime(n).at n=18A052229
- Primes such that the sum of the factorials of the digits is a perfect square.at n=24A052279
- Primes q of form q=10p+7, where p is also prime.at n=33A055783
- The first nontrivial (k>n+2) palindromic prime in both bases n and n+2 or -1 if it does not exist.at n=2A057199
- Primes starting and ending with 7.at n=20A062334
- Numbers k such that the first k binary digits found in the base-10 expansion of Pi form a prime (when the decimal point is ignored).at n=13A065832
- Primes arising in A083188.at n=2A083189
- Primes that are a concatenation of a prime and its first digit.at n=19A085414
- Numbers n which are prime and which when each digit is incremented by 2 with carries ignored yields another prime p with the same property.at n=40A088786
- Smallest prime equal to the sum of n distinct pairs of consecutive primes.at n=42A102725
- Primes from merging of 4 successive digits in decimal expansion of the Golden Ratio, (1+sqrt(5))/2.at n=34A103810
- Larger prime in pair prime(k) +/- k for some k.at n=18A107637