813191 has 4 divisors (see below), whose sum is σ = 826584. Its totient is φ = 799800.

The previous prime is 813167. The next prime is 813199. The reversal of 813191 is 191318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 813191 - 2¹⁰ = 812167 is a prime.

It is a super-2 number, since 2×813191² = 1322559204962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813199) 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, 6605 + ... + 6726.

It is an arithmetic number, because the mean of its divisors is an integer number (206646).

2⁸¹³¹⁹¹ is an apocalyptic number.

813191 is a deficient number, since it is larger than the sum of its proper divisors (13393).

813191 is a wasteful number, since it uses less digits than its factorization.

813191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13392.

The product of its digits is 216, while the sum is 23.

The square root of 813191 is about 901.7710352412. The cubic root of 813191 is about 93.3392244014.

The spelling of 813191 in words is "eight hundred thirteen thousand, one hundred ninety-one".