813389891 has 2 divisors, whose sum is σ = 813389892. Its totient is φ = 813389890.

The previous prime is 813389881. The next prime is 813389893. The reversal of 813389891 is 198983318.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 813389891 - 2¹⁰ = 813388867 is a prime.

It is a super-2 number, since 2×813389891² = 1323206229561983762, which contains 22 as substring.

Together with 813389893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (813389893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406694945 + 406694946.

It is an arithmetic number, because the mean of its divisors is an integer number (406694946).

Almost surely, 2^813389891 is an apocalyptic number.

813389891 is a deficient number, since it is larger than the sum of its proper divisors (1).

813389891 is an equidigital number, since it uses as much as digits as its factorization.

813389891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 373248, while the sum is 50.

The square root of 813389891 is about 28519.9910764362. The cubic root of 813389891 is about 933.4683344544.

The spelling of 813389891 in words is "eight hundred thirteen million, three hundred eighty-nine thousand, eight hundred ninety-one".