2565661 has 8 divisors (see below), whose sum is σ = 2944064. Its totient is φ = 2190240.

The previous prime is 2565649. The next prime is 2565671. The reversal of 2565661 is 1665652.

2565661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 2565661 - 2⁹ = 2565149 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2565611) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1606 + ... + 2776.

It is an arithmetic number, because the mean of its divisors is an integer number (368008).

2^2565661 is an apocalyptic number.

It is an amenable number.

2565661 is a deficient number, since it is larger than the sum of its proper divisors (378403).

2565661 is a wasteful number, since it uses less digits than its factorization.

2565661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1491.

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

The square root of 2565661 is about 1601.7680855854. The cubic root of 2565661 is about 136.8988366429.

Subtracting from 2565661 its reverse (1665652), we obtain a palindrome (900009).

The spelling of 2565661 in words is "two million, five hundred sixty-five thousand, six hundred sixty-one".