2166728865 has 32 divisors (see below), whose sum is σ = 3992288256. Its totient is φ = 982937280.

The previous prime is 2166728807. The next prime is 2166728873. The reversal of 2166728865 is 5688276612.

It is a happy number.

It is not a de Polignac number, because 2166728865 - 2⁸ = 2166728609 is a prime.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 65007 + ... + 92516.

It is an arithmetic number, because the mean of its divisors is an integer number (124759008).

Almost surely, 2^2166728865 is an apocalyptic number.

It is an amenable number.

2166728865 is a deficient number, since it is larger than the sum of its proper divisors (1825559391).

2166728865 is a wasteful number, since it uses less digits than its factorization.

2166728865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157669.

The product of its digits is 1935360, while the sum is 51.

The square root of 2166728865 is about 46548.1349250429. The cubic root of 2166728865 is about 1294.0017281418.

The spelling of 2166728865 in words is "two billion, one hundred sixty-six million, seven hundred twenty-eight thousand, eight hundred sixty-five".