2166306491 has 4 divisors (see below), whose sum is σ = 2173227912. Its totient is φ = 2159385072.

The previous prime is 2166306427. The next prime is 2166306523. The reversal of 2166306491 is 1946036612.

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 2166306491 - 2⁶ = 2166306427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2166306091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3460241 + ... + 3460866.

It is an arithmetic number, because the mean of its divisors is an integer number (543306978).

Almost surely, 2^2166306491 is an apocalyptic number.

2166306491 is a deficient number, since it is larger than the sum of its proper divisors (6921421).

2166306491 is an equidigital number, since it uses as much as digits as its factorization.

2166306491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6921420.

The product of its (nonzero) digits is 46656, while the sum is 38.

The square root of 2166306491 is about 46543.5977444804. The cubic root of 2166306491 is about 1293.9176400628.

The spelling of 2166306491 in words is "two billion, one hundred sixty-six million, three hundred six thousand, four hundred ninety-one".