2166343891 has 8 divisors (see below), whose sum is σ = 2237367168. Its totient is φ = 2095392000.

The previous prime is 2166343871. The next prime is 2166343901. The reversal of 2166343891 is 1983436612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2166343891 - 2⁵ = 2166343859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2166343811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47721 + ... + 81301.

It is an arithmetic number, because the mean of its divisors is an integer number (279670896).

Almost surely, 2^2166343891 is an apocalyptic number.

2166343891 is a deficient number, since it is larger than the sum of its proper divisors (71023277).

2166343891 is a wasteful number, since it uses less digits than its factorization.

2166343891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35693.

The product of its digits is 186624, while the sum is 43.

The square root of 2166343891 is about 46543.9995165865. Note that the first 3 decimals coincide. The cubic root of 2166343891 is about 1293.9250862608.

The spelling of 2166343891 in words is "two billion, one hundred sixty-six million, three hundred forty-three thousand, eight hundred ninety-one".