813891 has 16 divisors (see below), whose sum is σ = 1199520. Its totient is φ = 487680.

The previous prime is 813871. The next prime is 813893. The reversal of 813891 is 198318.

813891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 813891 - 2¹⁴ = 797507 is a prime.

It is a plaindrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813891.

It is not an unprimeable number, because it can be changed into a prime (813893) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1345 + ... + 1853.

It is an arithmetic number, because the mean of its divisors is an integer number (74970).

2⁸¹³⁸⁹¹ is an apocalyptic number.

813891 is a deficient number, since it is larger than the sum of its proper divisors (385629).

813891 is a wasteful number, since it uses less digits than its factorization.

813891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566.

The product of its digits is 1728, while the sum is 30.

The square root of 813891 is about 902.1590768817. The cubic root of 813891 is about 93.3659990535.

The spelling of 813891 in words is "eight hundred thirteen thousand, eight hundred ninety-one".