2165905 has 16 divisors (see below), whose sum is σ = 3127680. Its totient is φ = 1406592.

The previous prime is 2165903. The next prime is 2165921. The reversal of 2165905 is 5095612.

It is a cyclic number.

It is not a de Polignac number, because 2165905 - 2¹ = 2165903 is a prime.

It is a super-2 number, since 2×2165905² = 9382288938050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2165903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 964 + ... + 2293.

It is an arithmetic number, because the mean of its divisors is an integer number (195480).

2^2165905 is an apocalyptic number.

It is an amenable number.

2165905 is a deficient number, since it is larger than the sum of its proper divisors (961775).

2165905 is a wasteful number, since it uses less digits than its factorization.

2165905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3288.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 2165905 is about 1471.7013963437. The cubic root of 2165905 is about 129.3837699330.

The spelling of 2165905 in words is "two million, one hundred sixty-five thousand, nine hundred five".