7127
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
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7128
- 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
- 7126
- Möbius Function
- -1
- Radical
- 7127
- 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
- 163
- 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
- 913
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Euclid-Mullin sequence: a(1) = 2, a(n+1) is smallest prime factor of 1 + Product_{k=1..n} a(k).at n=22A000945
- Primes of the form 36*n^2 - 810*n + 2753, n >= 0, sorted.at n=13A022464
- Number of proper factorizations of p1^n*p2^6, where p1 and p2 are distinct primes.at n=10A031129
- 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 83.at n=23A031581
- Numbers whose set of base-13 digits is {2,3}.at n=27A032813
- Number of partitions satisfying cn(2,5) + cn(3,5) < cn(1,5) + cn(4,5).at n=33A039893
- Numbers having four 5's in base 6.at n=7A043392
- Primes with first digit 7.at n=30A045713
- Primes of the form 36*k^2 - 810*k + 2753, listed in order of increasing parameter k >= 0.at n=13A050268
- Euclid-Mullin sequence (A000945) with initial value a(1)=43 instead of a(1)=2.at n=22A051318
- Numbers k such that k! is divisible by the square of (f+d)!^2 for d = 0, 1 and 2 (and possibly larger d), where f = floor(k/2).at n=41A056068
- Primes p whose period of reciprocal equals (p-1)/7.at n=7A056212
- Primes starting and ending with 7.at n=7A062334
- Prime(n)*prime(2*n)+prime(n)+prime(2*n).at n=15A072672
- Primes of form prime(n)*prime(2*n)+prime(n)+prime(2*n).at n=8A072673
- Take A000040, omit commas: 23571113171923..., select 4-digit primes seen when scanning from left.at n=26A073037
- 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=37A073651
- Primes p such that 11 is the largest of all prime factors of the numbers between p and the next prime (cf. A052248).at n=14A080187
- Primes appearing as the concatenation of the last two digits of prime(A086102(n)) and the first two digits of prime(A086102(n)+1).at n=7A086103
- Smallest prime obtained by sandwiching n between a number with identical digits, or 0 if no such prime exists. Primes of the form k n k where all the digits of k are identical.at n=12A090287