256689855 has 24 divisors (see below), whose sum is σ = 447606432. Its totient is φ = 136077504.

The previous prime is 256689803. The next prime is 256689859. The reversal of 256689855 is 558986652.

It is not a de Polignac number, because 256689855 - 2⁸ = 256689599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256689859) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9564 + ... + 24593.

It is an arithmetic number, because the mean of its divisors is an integer number (18650268).

Almost surely, 2^256689855 is an apocalyptic number.

256689855 is a deficient number, since it is larger than the sum of its proper divisors (190916577).

256689855 is a wasteful number, since it uses less digits than its factorization.

256689855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34335 (or 34332 counting only the distinct ones).

The product of its digits is 5184000, while the sum is 54.

The square root of 256689855 is about 16021.5434649724. The cubic root of 256689855 is about 635.5302616058.

The spelling of 256689855 in words is "two hundred fifty-six million, six hundred eighty-nine thousand, eight hundred fifty-five".