256537081 has 2 divisors, whose sum is σ = 256537082. Its totient is φ = 256537080.

The previous prime is 256537063. The next prime is 256537109. The reversal of 256537081 is 180735652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 151290000 + 105247081 = 12300^2 + 10259^2 .

It is a cyclic number.

It is not a de Polignac number, because 256537081 - 2⁹ = 256536569 is a prime.

It is a super-2 number, since 2×256537081² = 131622547856001122, 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 256537081.

It is not a weakly prime, because it can be changed into another prime (256537051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128268540 + 128268541.

It is an arithmetic number, because the mean of its divisors is an integer number (128268541).

Almost surely, 2^256537081 is an apocalyptic number.

It is an amenable number.

256537081 is a deficient number, since it is larger than the sum of its proper divisors (1).

256537081 is an equidigital number, since it uses as much as digits as its factorization.

256537081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50400, while the sum is 37.

The square root of 256537081 is about 16016.7749874936. The cubic root of 256537081 is about 635.4041538187.

The spelling of 256537081 in words is "two hundred fifty-six million, five hundred thirty-seven thousand, eighty-one".