2165881 has 4 divisors (see below), whose sum is σ = 2170000. Its totient is φ = 2161764.

The previous prime is 2165873. The next prime is 2165893. The reversal of 2165881 is 1885612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2165881 - 2³ = 2165873 is a prime.

It is a super-2 number, since 2×2165881² = 9382081012322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2165081) 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, 1131 + ... + 2368.

It is an arithmetic number, because the mean of its divisors is an integer number (542500).

2^2165881 is an apocalyptic number.

It is an amenable number.

2165881 is a deficient number, since it is larger than the sum of its proper divisors (4119).

2165881 is an equidigital number, since it uses as much as digits as its factorization.

2165881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4118.

The product of its digits is 3840, while the sum is 31.

The square root of 2165881 is about 1471.6932424931. The cubic root of 2165881 is about 129.3832920386.

The spelling of 2165881 in words is "two million, one hundred sixty-five thousand, eight hundred eighty-one".