2165218665 has 16 divisors (see below), whose sum is σ = 3472361088. Its totient is φ = 1152112896.

The previous prime is 2165218661. The next prime is 2165218669. The reversal of 2165218665 is 5668125612.

It is an interprime number because it is at equal distance from previous prime (2165218661) and next prime (2165218669).

It is not a de Polignac number, because 2165218665 - 2² = 2165218661 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2165218661) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 160189 + ... + 173178.

It is an arithmetic number, because the mean of its divisors is an integer number (217022568).

Almost surely, 2^2165218665 is an apocalyptic number.

It is an amenable number.

2165218665 is a deficient number, since it is larger than the sum of its proper divisors (1307142423).

2165218665 is a wasteful number, since it uses less digits than its factorization.

2165218665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333808.

The product of its digits is 172800, while the sum is 42.

The square root of 2165218665 is about 46531.9101800044. The cubic root of 2165218665 is about 1293.7010205267.

The spelling of 2165218665 in words is "two billion, one hundred sixty-five million, two hundred eighteen thousand, six hundred sixty-five".