256581011 has 2 divisors, whose sum is σ = 256581012. Its totient is φ = 256581010.

The previous prime is 256581001. The next prime is 256581047. The reversal of 256581011 is 110185652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256581011 - 2¹⁰ = 256579987 is a prime.

It is not a weakly prime, because it can be changed into another prime (256581001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128290505 + 128290506.

It is an arithmetic number, because the mean of its divisors is an integer number (128290506).

Almost surely, 2^256581011 is an apocalyptic number.

256581011 is a deficient number, since it is larger than the sum of its proper divisors (1).

256581011 is an equidigital number, since it uses as much as digits as its factorization.

256581011 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 29.

The square root of 256581011 is about 16018.1463034897. The cubic root of 256581011 is about 635.4404211051.

The spelling of 256581011 in words is "two hundred fifty-six million, five hundred eighty-one thousand, eleven".