256565566 has 8 divisors (see below), whose sum is σ = 385864920. Its totient is φ = 127943928.

The previous prime is 256565539. The next prime is 256565587. The reversal of 256565566 is 665565652.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168481 + ... + 169996.

It is an arithmetic number, because the mean of its divisors is an integer number (48233115).

Almost surely, 2^256565566 is an apocalyptic number.

256565566 is a deficient number, since it is larger than the sum of its proper divisors (129299354).

256565566 is a wasteful number, since it uses less digits than its factorization.

256565566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338858.

The product of its digits is 1620000, while the sum is 46.

The square root of 256565566 is about 16017.6641867658. The cubic root of 256565566 is about 635.4276706497.

The spelling of 256565566 in words is "two hundred fifty-six million, five hundred sixty-five thousand, five hundred sixty-six".