6891 has 4 divisors (see below), whose sum is σ = 9192. Its totient is φ = 4592.
The previous prime is 6883. The next prime is 6899. The reversal of 6891 is 1986.
6891 is nontrivially palindromic in base 2.
It is a semiprime because it is the product of two primes.
It is an interprime number because it is at equal distance from previous prime (6883) and next prime (6899).
It is a cyclic number.
It is not a de Polignac number, because 6891 - 23 = 6883 is a prime.
It is a D-number.
6891 is a lucky number.
It is not an unprimeable number, because it can be changed into a prime (6899) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1146 + ... + 1151.
It is an arithmetic number, because the mean of its divisors is an integer number (2298).
26891 is an apocalyptic number.
6891 is the 53-rd centered pentagonal number.
6891 is a deficient number, since it is larger than the sum of its proper divisors (2301).
6891 is a wasteful number, since it uses less digits than its factorization.
6891 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 2300.
The product of its digits is 432, while the sum is 24.
The square root of 6891 is about 83.0120473184. The cubic root of 6891 is about 19.0295017214.
The spelling of 6891 in words is "six thousand, eight hundred ninety-one".
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