2091091 has 4 divisors (see below), whose sum is σ = 2182032. Its totient is φ = 2000152.

The previous prime is 2091053. The next prime is 2091097. The reversal of 2091091 is 1901902.

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

It is a cyclic number.

It is not a de Polignac number, because 2091091 - 2¹⁷ = 1960019 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2091097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45436 + ... + 45481.

It is an arithmetic number, because the mean of its divisors is an integer number (545508).

2^2091091 is an apocalyptic number.

2091091 is a deficient number, since it is larger than the sum of its proper divisors (90941).

2091091 is an equidigital number, since it uses as much as digits as its factorization.

2091091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90940.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 2091091 is about 1446.0605104905. The cubic root of 2091091 is about 127.8765696538.

Adding to 2091091 its reverse (1901902), we get a palindrome (3992993).

The spelling of 2091091 in words is "two million, ninety-one thousand, ninety-one".