256139885 has 16 divisors (see below), whose sum is σ = 311800320. Its totient is φ = 201976320.

The previous prime is 256139881. The next prime is 256139921. The reversal of 256139885 is 588931652.

256139885 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 256139885 - 2² = 256139881 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256139881) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 122045 + ... + 124125.

It is an arithmetic number, because the mean of its divisors is an integer number (19487520).

Almost surely, 2^256139885 is an apocalyptic number.

It is an amenable number.

256139885 is a deficient number, since it is larger than the sum of its proper divisors (55660435).

256139885 is a wasteful number, since it uses less digits than its factorization.

256139885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2428.

The product of its digits is 518400, while the sum is 47.

The square root of 256139885 is about 16004.3708092508. The cubic root of 256139885 is about 635.0760526431.

The spelling of 256139885 in words is "two hundred fifty-six million, one hundred thirty-nine thousand, eight hundred eighty-five".