2165281 has 4 divisors (see below), whose sum is σ = 2189700. Its totient is φ = 2140864.

The previous prime is 2165249. The next prime is 2165291. The reversal of 2165281 is 1825612.

2165281 = 1040² + 1041².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1083681 + 1081600 = 1041^2 + 1040^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165281 - 2⁵ = 2165249 is a prime.

It is a super-2 number, since 2×2165281² = 9376883617922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2165201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12076 + ... + 12253.

It is an arithmetic number, because the mean of its divisors is an integer number (547425).

2^2165281 is an apocalyptic number.

2165281 is the 1041-st centered square number.

It is an amenable number.

2165281 is a deficient number, since it is larger than the sum of its proper divisors (24419).

2165281 is an equidigital number, since it uses as much as digits as its factorization.

2165281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24418.

The product of its digits is 960, while the sum is 25.

The square root of 2165281 is about 1471.4893815451. The cubic root of 2165281 is about 129.3713435297.

The spelling of 2165281 in words is "two million, one hundred sixty-five thousand, two hundred eighty-one".