2166456665 has 12 divisors (see below), whose sum is σ = 2743780644. Its totient is φ = 1641944736.

The previous prime is 2166456653. The next prime is 2166456751. The reversal of 2166456665 is 5666546612.

It can be written as a sum of positive squares in 2 ways, for example, as 879656281 + 1286800384 = 29659^2 + 35872^2 .

It is not a de Polignac number, because 2166456665 - 2¹⁴ = 2166440281 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 598322 + ... + 601931.

It is an arithmetic number, because the mean of its divisors is an integer number (228648387).

Almost surely, 2^2166456665 is an apocalyptic number.

It is an amenable number.

2166456665 is a deficient number, since it is larger than the sum of its proper divisors (577323979).

2166456665 is a wasteful number, since it uses less digits than its factorization.

2166456665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1200296 (or 1200277 counting only the distinct ones).

The product of its digits is 1555200, while the sum is 47.

The square root of 2166456665 is about 46545.2109781447. The cubic root of 2166456665 is about 1293.9475386172.

The spelling of 2166456665 in words is "two billion, one hundred sixty-six million, four hundred fifty-six thousand, six hundred sixty-five".