256567081 has 4 divisors (see below), whose sum is σ = 256797892. Its totient is φ = 256336272.

The previous prime is 256567079. The next prime is 256567097. The reversal of 256567081 is 180765652.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22477081 + 234090000 = 4741^2 + 15300^2 .

It is a cyclic number.

It is not a de Polignac number, because 256567081 - 2¹ = 256567079 is a prime.

It is a super-2 number, since 2×256567081² = 131653334105721122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256567981) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113730 + ... + 115963.

It is an arithmetic number, because the mean of its divisors is an integer number (64199473).

Almost surely, 2^256567081 is an apocalyptic number.

It is an amenable number.

256567081 is a deficient number, since it is larger than the sum of its proper divisors (230811).

256567081 is a wasteful number, since it uses less digits than its factorization.

256567081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230810.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 256567081 is about 16017.7114782356. The cubic root of 256567081 is about 635.4289213644.

The spelling of 256567081 in words is "two hundred fifty-six million, five hundred sixty-seven thousand, eighty-one".