2165261 has 6 divisors (see below), whose sum is σ = 2518830. Its totient is φ = 1855896.

The previous prime is 2165249. The next prime is 2165291. The reversal of 2165261 is 1625612.

It can be written as a sum of positive squares in only one way, i.e., 1177225 + 988036 = 1085^2 + 994^2 .

It is not a de Polignac number, because 2165261 - 2¹⁴ = 2148877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2165201) 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 5 ways as a sum of consecutive naturals, for example, 22046 + ... + 22143.

It is an arithmetic number, because the mean of its divisors is an integer number (419805).

2^2165261 is an apocalyptic number.

It is an amenable number.

2165261 is a deficient number, since it is larger than the sum of its proper divisors (353569).

2165261 is an equidigital number, since it uses as much as digits as its factorization.

2165261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44203 (or 44196 counting only the distinct ones).

The product of its digits is 720, while the sum is 23.

The square root of 2165261 is about 1471.4825856938. The cubic root of 2165261 is about 129.3709452081.

The spelling of 2165261 in words is "two million, one hundred sixty-five thousand, two hundred sixty-one".