256388866 has 32 divisors (see below), whose sum is σ = 432190080. Its totient is φ = 113431296.

The previous prime is 256388851. The next prime is 256388893. The reversal of 256388866 is 668883652.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43360 + ... + 48916.

It is an arithmetic number, because the mean of its divisors is an integer number (13505940).

Almost surely, 2^256388866 is an apocalyptic number.

256388866 is a deficient number, since it is larger than the sum of its proper divisors (175801214).

256388866 is a wasteful number, since it uses less digits than its factorization.

256388866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5658.

The product of its digits is 3317760, while the sum is 52.

The square root of 256388866 is about 16012.1474512321. The cubic root of 256388866 is about 635.2817614158.

The spelling of 256388866 in words is "two hundred fifty-six million, three hundred eighty-eight thousand, eight hundred sixty-six".