2166091 has 4 divisors (see below), whose sum is σ = 2224672. Its totient is φ = 2107512.

The previous prime is 2166077. The next prime is 2166113. The reversal of 2166091 is 1906612.

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 2166091 - 2⁷ = 2165963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2166041) 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, 29235 + ... + 29308.

It is an arithmetic number, because the mean of its divisors is an integer number (556168).

2^2166091 is an apocalyptic number.

2166091 is a deficient number, since it is larger than the sum of its proper divisors (58581).

2166091 is an equidigital number, since it uses as much as digits as its factorization.

2166091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58580.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 2166091 is about 1471.7645871538. The cubic root of 2166091 is about 129.3874734953.

The spelling of 2166091 in words is "two million, one hundred sixty-six thousand, ninety-one".