256661013 has 16 divisors (see below), whose sum is σ = 391326336. Its totient is φ = 146579520.

The previous prime is 256660973. The next prime is 256661029. The reversal of 256661013 is 310166652.

256661013 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a de Polignac number, because none of the positive numbers 2^k-256661013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256661213) 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, 69883 + ... + 73463.

It is an arithmetic number, because the mean of its divisors is an integer number (24457896).

Almost surely, 2^256661013 is an apocalyptic number.

It is an amenable number.

256661013 is a deficient number, since it is larger than the sum of its proper divisors (134665323).

256661013 is a wasteful number, since it uses less digits than its factorization.

256661013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7004.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 256661013 is about 16020.6433391422. The cubic root of 256661013 is about 635.5064577169.

The spelling of 256661013 in words is "two hundred fifty-six million, six hundred sixty-one thousand, thirteen".