256271581 has 2 divisors, whose sum is σ = 256271582. Its totient is φ = 256271580.

The previous prime is 256271573. The next prime is 256271591. The reversal of 256271581 is 185172652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 256160025 + 111556 = 16005^2 + 334^2 .

It is a cyclic number.

It is not a de Polignac number, because 256271581 - 2³ = 256271573 is a prime.

It is a super-2 number, since 2×256271581² = 131350246456479122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256271581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256271531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128135790 + 128135791.

It is an arithmetic number, because the mean of its divisors is an integer number (128135791).

Almost surely, 2^256271581 is an apocalyptic number.

It is an amenable number.

256271581 is a deficient number, since it is larger than the sum of its proper divisors (1).

256271581 is an equidigital number, since it uses as much as digits as its factorization.

256271581 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33600, while the sum is 37.

The square root of 256271581 is about 16008.4846565813. The cubic root of 256271581 is about 635.1848768321.

The spelling of 256271581 in words is "two hundred fifty-six million, two hundred seventy-one thousand, five hundred eighty-one".