9907
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 9908
- 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
- 9906
- Möbius Function
- -1
- Radical
- 9907
- 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
- 42
- 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
- 1222
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes of the form m^2 + 3m + 9, where m can be positive or negative.at n=31A005471
- 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 99.at n=10A031597
- Lower prime of a pair of consecutive primes having a difference of 16.at n=32A031934
- Discriminants of imaginary quadratic fields with class number 15 (negated).at n=35A046012
- Primes p such that the decimal digits of p^2 can be partitioned into two or more nonzero squares.at n=27A048646
- Number of primes between n^4 and (n+1)^4.at n=32A061235
- Treated as strings, n begins with Floor(sqrt(n)).at n=30A069086
- Numbers k such that average of prime(k) and prime(k+1) is a perfect square.at n=40A076692
- a(n) = largest prime <= n*prime(n).at n=46A079780
- Numbers n such that 3^n + 2^(n-1) is prime.at n=38A082103
- Primes p such that the sum of the digits of p is not prime, but the sum of the squares of the digits of p is prime.at n=16A091362
- Primes p such that the sum of the digits of p is not prime, but the sum of the cubes of the digits of p is prime.at n=12A091365
- First occurrence of n in A093723, or -1 if n does not occur.at n=52A093724
- Primes p equal to the sum of two successive sexy primes - 1 such that p - 6 is also prime.at n=19A104047
- Primes p such that the polynomial x^4-x^3-x^2-x-1 mod p has 4 distinct zeros.at n=38A106280
- Primes that do not divide any term of the Lucas 4-step sequence A073817.at n=9A106300
- a(n) = C(n,7) + C(n,6) + C(n,5) + C(n,4) + C(n,3) + C(n,2) + C(n,1).at n=14A116082
- Smallest prime p such that p^n is equal to the sum of 3 consecutive primes.at n=31A122706
- Triangle read by rows: T(n,k) is the number of ordered trees with n edges, with thinning limbs and with root of degree k (1<=k<=n). An ordered tree with thinning limbs is such that if a node has k children, all its children have at most k children.at n=68A124328
- a(n) = 15*n^2 - 9*n + 1.at n=26A134154