7541
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
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7542
- 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
- 7540
- Möbius Function
- -1
- Radical
- 7541
- 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
- 132
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 956
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 29.at n=18A020368
- 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=89A049336
- p, p+6 and p+8 are all primes (A046138) but p+2 is not.at n=40A049438
- Primes with distinct digits in descending order.at n=35A052014
- Primes p from A031924 such that A052180(primepi(p)) = 19.at n=12A052235
- McKay-Thompson series of class 18b for the Monster group.at n=17A058537
- Primes p such that x^29 = 2 has no solution mod p.at n=31A059256
- Primes p such that |p - q| is a square, where q is the reversal of p.at n=27A059798
- Triangle defined in A064641 read by rows.at n=33A064642
- Numbers n such that the Eisenstein integer (1 - ω)^n - 1 has prime norm, where ω = -1/2 + sqrt(-3)/2.at n=19A066408
- a(0) = 1; for n>0, a(n) = 1 + coefficient of x^n in expansion of 1/Product_{ n >= 2, n not of the form 2^k-1 } (1-x^n).at n=51A078658
- Numerators of triangular array: T(n,1)=T(n,n)=1/n and T(n,k)=T(n-1,k-1)+T(n-1,k), 1<k<n.at n=58A080044
- Non-palindromic primes which on subtracting their reversal give perfect squares.at n=10A080177
- Primes from merging of 4 successive digits in decimal expansion of the Euler-Mascheroni constant A001620.at n=32A104938
- Larger of two consecutive Sophie Germain primes with the same digital sum.at n=19A118507
- Primes for which the weight as defined in A117078 is 11 and the gap as defined in A001223 is 6.at n=15A119597
- Expansion of x*(1+9*x+2*x^2)/((1-x)*(1-3*x+x^2)).at n=7A121990
- Primes p such that 3^p + 3^((p + 1)/2) + 1 is prime.at n=12A125739
- Primes p such that p = prime(n+3)=(prime(n+6)+prime(n))/2.at n=42A126240
- Sums of three consecutive heptagonal numbers.at n=31A129111