891111121 has 6 divisors (see below), whose sum is σ = 898199250. Its totient is φ = 884078496.

The previous prime is 891111113. The next prime is 891111127. The reversal of 891111121 is 121111198.

891111121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 816530625 + 74580496 = 28575^2 + 8636^2 .

It is not a de Polignac number, because 891111121 - 2³ = 891111113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (891111127) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11496 + ... + 43753.

It is an arithmetic number, because the mean of its divisors is an integer number (149699875).

Almost surely, 2^891111121 is an apocalyptic number.

It is an amenable number.

891111121 is a deficient number, since it is larger than the sum of its proper divisors (7088129).

891111121 is an equidigital number, since it uses as much as digits as its factorization.

891111121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55503 (or 55376 counting only the distinct ones).

The product of its digits is 144, while the sum is 25.

The square root of 891111121 is about 29851.4844019523. The cubic root of 891111121 is about 962.3003000769.

The spelling of 891111121 in words is "eight hundred ninety-one million, one hundred eleven thousand, one hundred twenty-one".