256521728794 has 8 divisors (see below), whose sum is σ = 384838959060. Its totient is φ = 128242075776.

The previous prime is 256521728779. The next prime is 256521728821. The reversal of 256521728794 is 497827125652.

It can be written as a sum of positive squares in 2 ways, for example, as 228670458025 + 27851270769 = 478195^2 + 166887^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 9377239 + ... + 9404554.

Almost surely, 2^256521728794 is an apocalyptic number.

256521728794 is a deficient number, since it is larger than the sum of its proper divisors (128317230266).

256521728794 is a wasteful number, since it uses less digits than its factorization.

256521728794 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18788624.

The product of its digits is 16934400, while the sum is 58.

The spelling of 256521728794 in words is "two hundred fifty-six billion, five hundred twenty-one million, seven hundred twenty-eight thousand, seven hundred ninety-four".