2111891 has 4 divisors (see below), whose sum is σ = 2151792. Its totient is φ = 2071992.

The previous prime is 2111873. The next prime is 2111897. The reversal of 2111891 is 1981112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2111891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2111897) 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, 19871 + ... + 19976.

It is an arithmetic number, because the mean of its divisors is an integer number (537948).

2^2111891 is an apocalyptic number.

2111891 is a deficient number, since it is larger than the sum of its proper divisors (39901).

2111891 is an equidigital number, since it uses as much as digits as its factorization.

2111891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39900.

The product of its digits is 144, while the sum is 23.

The square root of 2111891 is about 1453.2346679047. The cubic root of 2111891 is about 128.2991659571.

The spelling of 2111891 in words is "two million, one hundred eleven thousand, eight hundred ninety-one".