1931
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1932
- 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
- 1930
- Möbius Function
- -1
- Radical
- 1931
- 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
- 143
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 294
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p == 3, 9, 11 (mod 20) such that 2p+1 is also prime.at n=29A000355
- Number of nonnegative solutions to x^2 + y^2 <= n^2.at n=49A000603
- Smallest prime p==3 (mod 8) such that Q(sqrt(-p)) has class number 2n+1.at n=10A002148
- Lucasian primes: p == 3 (mod 4) with 2*p+1 prime.at n=30A002515
- a(n) = 3^(n-1) - 2^n.at n=7A003063
- a(n) = floor(n*phi^12), where phi is the golden ratio, A001622.at n=6A004927
- Numbers n such that n, 2n+1, and 4n+3 all prime.at n=19A007700
- Coordination sequence T1 for Zeolite Code MFI.at n=28A008161
- Coordination sequence T4 for Zeolite Code MTT.at n=27A008192
- Coordination sequence T3 for Zeolite Code CON.at n=31A009870
- Numbers in which every prefix (in base 10) is 1 or a prime.at n=47A012883
- Cardinality of the permutation (k, k-1, ..., 2, 1)(n, n-1, ..., k+1) in an exchange shuffle applied in all n^n possible ways to (1,2,...,n).at n=7A013560
- Smallest nonempty set S containing prime divisors of 8k+3 for each k in S.at n=49A020617
- Place where n-th 1 occurs in A023127.at n=39A022789
- Primes that remain prime through 2 iterations of function f(x) = 4x + 3.at n=27A023250
- Primes that remain prime through 2 iterations of function f(x) = 9x + 8.at n=28A023267
- Primes that remain prime through 2 iterations of function f(x) = 9x + 10.at n=37A023268
- Primes that remain prime through 3 iterations of function f(x) = 5x + 6.at n=13A023285
- Discriminants of quartic fields with 2 complex conjugates (negated).at n=44A023681
- T(2n,n-2), T given by A026714.at n=4A026717