256561535 has 16 divisors (see below), whose sum is σ = 328486752. Its totient is φ = 191692800.

The previous prime is 256561507. The next prime is 256561537. The reversal of 256561535 is 535165652.

It is not a de Polignac number, because 256561535 - 2¹² = 256557439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256561537) 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, 386 + ... + 22655.

It is an arithmetic number, because the mean of its divisors is an integer number (20530422).

Almost surely, 2^256561535 is an apocalyptic number.

256561535 is a deficient number, since it is larger than the sum of its proper divisors (71925217).

256561535 is a wasteful number, since it uses less digits than its factorization.

256561535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23194.

The product of its digits is 135000, while the sum is 38.

The square root of 256561535 is about 16017.5383564392. The cubic root of 256561535 is about 635.4243428163.

The spelling of 256561535 in words is "two hundred fifty-six million, five hundred sixty-one thousand, five hundred thirty-five".