2165743665 has 48 divisors (see below), whose sum is σ = 3807917568. Its totient is φ = 1138572288.

The previous prime is 2165743661. The next prime is 2165743729. The reversal of 2165743665 is 5663475612.

2165743665 is a `hidden beast` number, since 2 + 16 + 574 + 3 + 6 + 65 = 666.

It is not a de Polignac number, because 2165743665 - 2² = 2165743661 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2165743665.

It is not an unprimeable number, because it can be changed into a prime (2165743661) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1072737 + ... + 1074753.

It is an arithmetic number, because the mean of its divisors is an integer number (79331616).

Almost surely, 2^2165743665 is an apocalyptic number.

It is an amenable number.

2165743665 is a deficient number, since it is larger than the sum of its proper divisors (1642173903).

2165743665 is a wasteful number, since it uses less digits than its factorization.

2165743665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2358 (or 2355 counting only the distinct ones).

The product of its digits is 907200, while the sum is 45.

The square root of 2165743665 is about 46537.5511280944. The cubic root of 2165743665 is about 1293.8055731922.

The spelling of 2165743665 in words is "two billion, one hundred sixty-five million, seven hundred forty-three thousand, six hundred sixty-five".