256191409007 has 4 divisors (see below), whose sum is σ = 256203161760. Its totient is φ = 256179656256.

The previous prime is 256191408971. The next prime is 256191409013. The reversal of 256191409007 is 700904191652.

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

It is a cyclic number.

It is not a de Polignac number, because 256191409007 - 2⁸ = 256191408751 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 (256191409027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5843618 + ... + 5887295.

It is an arithmetic number, because the mean of its divisors is an integer number (64050790440).

Almost surely, 2^256191409007 is an apocalyptic number.

256191409007 is a deficient number, since it is larger than the sum of its proper divisors (11752753).

256191409007 is a wasteful number, since it uses less digits than its factorization.

256191409007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11752752.

The product of its (nonzero) digits is 136080, while the sum is 44.

The spelling of 256191409007 in words is "two hundred fifty-six billion, one hundred ninety-one million, four hundred nine thousand, seven".