811691389 has 4 divisors (see below), whose sum is σ = 812659680. Its totient is φ = 810723100.

The previous prime is 811691371. The next prime is 811691443. The reversal of 811691389 is 983196118.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 811691389 - 2⁹ = 811690877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811691339) 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, 482887 + ... + 484564.

It is an arithmetic number, because the mean of its divisors is an integer number (203164920).

Almost surely, 2^811691389 is an apocalyptic number.

It is an amenable number.

811691389 is a deficient number, since it is larger than the sum of its proper divisors (968291).

811691389 is an equidigital number, since it uses as much as digits as its factorization.

811691389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 968290.

The product of its digits is 93312, while the sum is 46.

The square root of 811691389 is about 28490.1981214592. The cubic root of 811691389 is about 932.8181326538.

The spelling of 811691389 in words is "eight hundred eleven million, six hundred ninety-one thousand, three hundred eighty-nine".