15923
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15924
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15922
- Möbius Function
- -1
- Radical
- 15923
- 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
- 146
- 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
- 1857
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Powers of fifth root of 6 rounded to nearest integer.at n=27A018130
- Powers of fifth root of 6 rounded up.at n=27A018131
- a(n) is the least odd number of the form p + k^2 with p prime and k > 0 which can be represented in exactly n different ways.at n=41A059400
- Least number which may be expressed as the sum of a prime number and a nonzero square in exactly n different ways.at n=40A064283
- a(n) = if Floor[(2*Pi/E)*m^2] is prime then Floor[(2*Pi/E)*m^2].at n=8A090434
- Irregular primes whose indices are irregular primes of order one.at n=48A090869
- Numbers k such that k^4 contains a pandigital substring.at n=31A115934
- Expansion of (17-25*x-23*x^2+133*x^3)/(1-x)^4.at n=11A118587
- Primes congruent to 15 mod 41.at n=40A142212
- Primes congruent to 13 mod 43.at n=41A142262
- Primes congruent to 37 mod 47.at n=41A142388
- Primes congruent to 23 mod 53.at n=34A142553
- Primes congruent to 52 mod 59.at n=36A142779
- Primes congruent to 2 mod 61.at n=28A142800
- Primes of the form : 2*p+1=p1(prime), 2*p1+3=p2(prime), 2*p2+5=p3(prime).at n=30A143912
- Prime numbers p such that p - 1 is the fourth a-figurate number and nineteenth b-figurate number for some a and b.at n=15A144327
- Fibonacci sequence beginning 41, 43.at n=13A157194
- a(n) = 3*b_3(n)+2, where b_3 lists the zeros of the sequence A261303: u(n+1)=abs(u(n)-gcd(u(n),3*n+2)), u(1)=1.at n=6A186255
- Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=16A192970
- Primes p with property that there exists a number d>0 such that numbers p-k*d, k=1...7, are seven primes.at n=17A216590