2561565 has 16 divisors (see below), whose sum is σ = 4118400. Its totient is φ = 1359552.

The previous prime is 2561551. The next prime is 2561593. The reversal of 2561565 is 5651652.

2561565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2561565 - 2⁴ = 2561549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5616 + ... + 6054.

It is an arithmetic number, because the mean of its divisors is an integer number (257400).

2^2561565 is an apocalyptic number.

It is an amenable number.

2561565 is a deficient number, since it is larger than the sum of its proper divisors (1556835).

2561565 is a wasteful number, since it uses less digits than its factorization.

2561565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 836.

The product of its digits is 9000, while the sum is 30.

The square root of 2561565 is about 1600.4889877784. The cubic root of 2561565 is about 136.8259462259.

The spelling of 2561565 in words is "two million, five hundred sixty-one thousand, five hundred sixty-five".