1973
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1974
- 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
- 1972
- Möbius Function
- -1
- Radical
- 1973
- 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
- 50
- 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
- 298
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = a(n-1) + a(n-2) + 1, with a(0) = a(1) = 1.at n=15A001595
- Odd numbers not of form p + 2^k (de Polignac numbers).at n=45A006285
- Where the prime race among 5k+1, ..., 5k+4 changes leader.at n=17A007353
- Primes of form 3*k^2 - 3*k + 23.at n=23A007637
- Coordination sequence T1 for Zeolite Code LEV.at n=33A008127
- Coordination sequence T1 for Zeolite Code LTL.at n=32A008138
- Coordination sequence T5 for Zeolite Code DFO.at n=34A009879
- Numbers in which every prefix (in base 10) is 1 or a prime.at n=49A012883
- Numbers k such that the continued fraction for sqrt(k) has period 11.at n=18A020350
- Smallest nonempty set S containing prime divisors of 7k+6 for each k in S.at n=43A020611
- Primes that remain prime through 2 iterations of function f(x) = 3x + 8.at n=30A023248
- Primes that remain prime through 2 iterations of function f(x) = 9x + 4.at n=31A023266
- Primes that remain prime through 3 iterations of function f(x) = 9x + 4.at n=12A023297
- a(n) = [ 1/(2*t(n+1) - t(n) - t(n+2)) ], where t(n) = tan(Pi/2 - 1/n) satisfies n-1 < t(n) < n for all n >= 1.at n=9A024817
- Palindromic primes in base 15.at n=26A029982
- Primes such that in p^2 the parity of digits alternates.at n=25A030145
- Prime p concatenated with next prime is also prime.at n=42A030459
- a(n) = prime(10*n - 2).at n=29A031384
- a(n) = prime(7*n-3).at n=42A031388
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 3.at n=25A031416