2661865 has 4 divisors (see below), whose sum is σ = 3194244. Its totient is φ = 2129488.

The previous prime is 2661863. The next prime is 2661871. The reversal of 2661865 is 5681662.

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 1937664 + 724201 = 1392^2 + 851^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661865 - 2¹ = 2661863 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2661865.

It is not an unprimeable number, because it can be changed into a prime (2661863) 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, 266182 + ... + 266191.

It is an arithmetic number, because the mean of its divisors is an integer number (798561).

2^2661865 is an apocalyptic number.

It is an amenable number.

2661865 is a deficient number, since it is larger than the sum of its proper divisors (532379).

2661865 is an equidigital number, since it uses as much as digits as its factorization.

2661865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532378.

The product of its digits is 17280, while the sum is 34.

The square root of 2661865 is about 1631.5222952813. The cubic root of 2661865 is about 138.5889726204.

The spelling of 2661865 in words is "two million, six hundred sixty-one thousand, eight hundred sixty-five".