691110891 has 12 divisors (see below), whose sum is σ = 998612160. Its totient is φ = 460583280.

The previous prime is 691110887. The next prime is 691110941. The reversal of 691110891 is 198011196.

691110891 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 691110891 - 2² = 691110887 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691110821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18801 + ... + 41661.

It is an arithmetic number, because the mean of its divisors is an integer number (83217680).

Almost surely, 2^691110891 is an apocalyptic number.

691110891 is a deficient number, since it is larger than the sum of its proper divisors (307501269).

691110891 is a wasteful number, since it uses less digits than its factorization.

691110891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26226 (or 26223 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 36.

The square root of 691110891 is about 26288.9880177994. The cubic root of 691110891 is about 884.1295626284.

The spelling of 691110891 in words is "six hundred ninety-one million, one hundred ten thousand, eight hundred ninety-one".