16631
domain: N
Properties
Digital Properties
- Digit Count
- 5
- 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
- 16632
- 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
- 16630
- Möbius Function
- -1
- Radical
- 16631
- 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
- 203
- 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
- 1923
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers whose least quadratic nonresidue (A020649) is 17.at n=11A025026
- Start of a string of exactly 2 consecutive (but disjoint) pairs of twin primes.at n=35A035790
- Primes p that have at least four primitive roots that are not primitive roots mod p^2.at n=1A060520
- Primes with 19 as smallest positive primitive root.at n=14A061331
- Near twin primes of order 18: twin primes (p, p+2) such that p+18 and p+20 are primes.at n=26A079304
- 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=19A080187
- a(n)=(-1)^n(1 - (1/12)n(n + 1)(12 - n + n^2)).at n=21A080275
- Primes of the form pq - 6, where p and q are consecutive primes.at n=14A099775
- Odd numbers n for which 17 is the smallest i (>= 1) with Jacobi symbol J(i,n) getting either a value 0 or -1.at n=18A112077
- List of triples of primes with common difference 12.at n=35A128312
- Intersection of A061068 and A064270.at n=33A128996
- Primes p such that p+2, p*(p+2)+18 and p*(p+2)+20 are also prime.at n=2A130737
- a(1)=1; for n>=2, a(n) = the largest prime dividing n*a(n-1) + 1.at n=32A134487
- Lesser of twin primes isolated from neighboring primes by +- 10 (or more).at n=31A138063
- Primes congruent to 40 mod 47.at n=40A142391
- Primes congruent to 42 mod 53.at n=34A142572
- Primes congruent to 52 mod 59.at n=37A142779
- Primes congruent to 39 mod 61.at n=27A142837
- INVERT transform of A002321, Mertens's function.at n=22A144031
- Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 0100-1100-1111 pattern in any orientation.at n=15A146787