15973
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15974
- 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
- 15972
- Möbius Function
- -1
- Radical
- 15973
- 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
- 53
- 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
- 1861
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of semigroups of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).at n=6A001423
- Numbers k such that the continued fraction for sqrt(k) has period 47.at n=22A020386
- Sums of distinct powers of 11.at n=25A033047
- Sums of 3 distinct powers of 11.at n=7A038491
- Let (p1,p2), (p3,p4) be pairs of twin primes with p1*p2=p3+p4-1; sequence gives values of p2.at n=19A047977
- Number of step cyclic shifted sequence structures using a maximum of four different symbols.at n=11A056431
- The first of two consecutive primes with equal digital sums.at n=37A066540
- Primes p such that the period of the decimal expansion of 1/p is a square.at n=25A072858
- a(n) = prime(2*n*(n+1)+1).at n=30A078746
- Primes of the form 1+(1+p)*p^e, p prime and e>0.at n=20A087196
- Prime numbers which when written in base 7 have a composite digit-sum.at n=24A096790
- Primes p such that little googol + p is prime.at n=34A108255
- Primes with at least one of each odd digit and no even digits.at n=4A108418
- Primes p for which the period length of 1/p is a perfect power, A001597.at n=32A128948
- Primes of the form 210n + 13.at n=38A140841
- Primes congruent to 40 mod 47.at n=37A142391
- Primes congruent to 20 mod 53.at n=32A142550
- Primes congruent to 43 mod 59.at n=35A142770
- Primes congruent to 52 mod 61.at n=30A142850
- Expansion of x/((1 - x - x^4)*(1 - x)^6).at n=12A145135