5641
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 5642
- 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
- 5640
- Möbius Function
- -1
- Radical
- 5641
- 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
- 41
- 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
- 741
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Artiads: the primes p == 1 (mod 5) for which Fibonacci((p-1)/5) is divisible by p.at n=34A001583
- Centered 4-dimensional orthoplex numbers (crystal ball sequence for 4-dimensional cubic lattice).at n=9A001846
- Coordination sequence T1 for Zeolite Code MON.at n=46A008181
- Crystal ball sequence for 9-dimensional cubic lattice.at n=4A008419
- a(n) = prime(n*(n+1)/2).at n=37A011756
- Primes p such that p, p+6, p+12, p+18 are all primes.at n=20A023271
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 54 ones.at n=6A031822
- Number of partitions in parts not of the form 19k, 19k+1 or 19k-1. Also number of partitions with no part of size 1 and differences between parts at distance 8 are greater than 1.at n=39A035970
- a(n) = A047980(2n).at n=28A047981
- n plus a googol is prime.at n=16A049014
- Euclid-Mullin sequence (A000945) with initial value a(1)=5 instead of a(1)=2.at n=19A051308
- Primes p for which the period of reciprocal 1/p is (p-1)/12.at n=8A056217
- Primes p such that x^47 = 2 has no solution mod p.at n=17A059257
- Primes p such that x^5 == 2 (mod p) has five solutions.at n=37A059858
- Distinct (non-overlapping) twin Harshad numbers whose sum is prime.at n=29A060288
- Primes which are sums of twin Harshad numbers (includes overlaps).at n=34A060290
- Primes with 14 as smallest positive primitive root.at n=5A061327
- Primes of form Sum_{k=1..n} (prime(k)+1).at n=24A062736
- Number of nodes in virtual, "optimal", chordal graphs of diameter 4 and degree n+1.at n=16A067956
- Define the composite field of a prime q to be f(q) = (t,s) if p, q, r are three consecutive primes and q-p = t and r-q = s. This is a sequence of primes q with field (2,6).at n=31A073650