2605561 has 4 divisors (see below), whose sum is σ = 2977792. Its totient is φ = 2233332.

The previous prime is 2605543. The next prime is 2605579. The reversal of 2605561 is 1655062.

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 an interprime number because it is at equal distance from previous prime (2605543) and next prime (2605579).

It is a cyclic number.

It is not a de Polignac number, because 2605561 - 2⁵ = 2605529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2605501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 186105 + ... + 186118.

It is an arithmetic number, because the mean of its divisors is an integer number (744448).

2^2605561 is an apocalyptic number.

It is an amenable number.

2605561 is a deficient number, since it is larger than the sum of its proper divisors (372231).

2605561 is an equidigital number, since it uses as much as digits as its factorization.

2605561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 372230.

The product of its (nonzero) digits is 1800, while the sum is 25.

The square root of 2605561 is about 1614.1750214893. The cubic root of 2605561 is about 137.6048522548.

The spelling of 2605561 in words is "two million, six hundred five thousand, five hundred sixty-one".