2190891 has 4 divisors (see below), whose sum is σ = 2921192. Its totient is φ = 1460592.

The previous prime is 2190887. The next prime is 2190901. The reversal of 2190891 is 1980912.

2190891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 2190891 - 2² = 2190887 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2190821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 365146 + ... + 365151.

It is an arithmetic number, because the mean of its divisors is an integer number (730298).

2^2190891 is an apocalyptic number.

2190891 is a deficient number, since it is larger than the sum of its proper divisors (730301).

2190891 is an equidigital number, since it uses as much as digits as its factorization.

2190891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730300.

The product of its (nonzero) digits is 1296, while the sum is 30.

The square root of 2190891 is about 1480.1658690836. The cubic root of 2190891 is about 129.8793950491.

It can be divided in two parts, 2190 and 891, that added together give a triangular number (3081 = T₇₈).

The spelling of 2190891 in words is "two million, one hundred ninety thousand, eight hundred ninety-one".