2165665 has 8 divisors (see below), whose sum is σ = 2614248. Its totient is φ = 1722240.

The previous prime is 2165663. The next prime is 2165671. The reversal of 2165665 is 5665612.

It can be written as a sum of positive squares in 4 ways, for example, as 239121 + 1926544 = 489^2 + 1388^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2165665 - 2¹ = 2165663 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2165663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 292 + ... + 2101.

It is an arithmetic number, because the mean of its divisors is an integer number (326781).

2^2165665 is an apocalyptic number.

It is an amenable number.

2165665 is a deficient number, since it is larger than the sum of its proper divisors (448583).

2165665 is a wasteful number, since it uses less digits than its factorization.

2165665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2579.

The product of its digits is 10800, while the sum is 31.

The square root of 2165665 is about 1471.6198558052. The cubic root of 2165665 is about 129.3789908296.

The spelling of 2165665 in words is "two million, one hundred sixty-five thousand, six hundred sixty-five".