2561566 has 8 divisors (see below), whose sum is σ = 4391280. Its totient is φ = 1097808.

The previous prime is 2561551. The next prime is 2561593. The reversal of 2561566 is 6651652.

2561566 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 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 3 ways as a sum of consecutive naturals, for example, 91471 + ... + 91498.

It is an arithmetic number, because the mean of its divisors is an integer number (548910).

2^2561566 is an apocalyptic number.

2561566 is a deficient number, since it is larger than the sum of its proper divisors (1829714).

2561566 is a wasteful number, since it uses less digits than its factorization.

2561566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182978.

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

The square root of 2561566 is about 1600.4893001829. The cubic root of 2561566 is about 136.8259640309.

The spelling of 2561566 in words is "two million, five hundred sixty-one thousand, five hundred sixty-six".