2165409 has 12 divisors (see below), whose sum is σ = 3312036. Its totient is φ = 1358592.

The previous prime is 2165393. The next prime is 2165413. The reversal of 2165409 is 9045612.

2165409 is a `hidden beast` number, since 2 + 1 + 654 + 0 + 9 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1272384 + 893025 = 1128^2 + 945^2 .

It is not a de Polignac number, because 2165409 - 2⁴ = 2165393 is a prime.

It is a super-2 number, since 2×2165409² = 9377992274562, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2165809) 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 11 ways as a sum of consecutive naturals, for example, 6924 + ... + 7229.

It is an arithmetic number, because the mean of its divisors is an integer number (276003).

2^2165409 is an apocalyptic number.

It is an amenable number.

2165409 is a deficient number, since it is larger than the sum of its proper divisors (1146627).

2165409 is a wasteful number, since it uses less digits than its factorization.

2165409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14176 (or 14173 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 2165409 is about 1471.5328742505. The cubic root of 2165409 is about 129.3738927301.

It can be divided in two parts, 216 and 5409, that added together give a square (5625 = 75²).

The spelling of 2165409 in words is "two million, one hundred sixty-five thousand, four hundred nine".