256789566551 has 12 divisors (see below), whose sum is σ = 300018836520. Its totient is φ = 219144174480.

The previous prime is 256789566529. The next prime is 256789566571. The reversal of 256789566551 is 155665987652.

It is a de Polignac number, because none of the positive numbers 2^k-256789566551 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 (256789566511) 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 11 ways as a sum of consecutive naturals, for example, 11431145 + ... + 11453586.

It is an arithmetic number, because the mean of its divisors is an integer number (25001569710).

Almost surely, 2^256789566551 is an apocalyptic number.

256789566551 is a deficient number, since it is larger than the sum of its proper divisors (43229269969).

256789566551 is a wasteful number, since it uses less digits than its factorization.

256789566551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22884974 (or 22884967 counting only the distinct ones).

The product of its digits is 136080000, while the sum is 65.

The spelling of 256789566551 in words is "two hundred fifty-six billion, seven hundred eighty-nine million, five hundred sixty-six thousand, five hundred fifty-one".