2117865 has 16 divisors (see below), whose sum is σ = 3407616. Its totient is φ = 1123200.

The previous prime is 2117861. The next prime is 2117887. The reversal of 2117865 is 5687112.

It is not a de Polignac number, because 2117865 - 2² = 2117861 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2117861) 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, 3805 + ... + 4325.

It is an arithmetic number, because the mean of its divisors is an integer number (212976).

2^2117865 is an apocalyptic number.

It is an amenable number.

2117865 is a deficient number, since it is larger than the sum of its proper divisors (1289751).

2117865 is a wasteful number, since it uses less digits than its factorization.

2117865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 800.

The product of its digits is 3360, while the sum is 30.

The square root of 2117865 is about 1455.2886311657. The cubic root of 2117865 is about 128.4200272523.

The spelling of 2117865 in words is "two million, one hundred seventeen thousand, eight hundred sixty-five".