256221042664 has 8 divisors (see below), whose sum is σ = 480414455010. Its totient is φ = 128110521328.

The previous prime is 256221042611. The next prime is 256221042673. The reversal of 256221042664 is 466240122652.

It can be written as a sum of positive squares in only one way, i.e., 241759056100 + 14461986564 = 491690^2 + 120258^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16013815159 + ... + 16013815174.

Almost surely, 2^256221042664 is an apocalyptic number.

It is an amenable number.

256221042664 is a deficient number, since it is larger than the sum of its proper divisors (224193412346).

256221042664 is a wasteful number, since it uses less digits than its factorization.

256221042664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32027630339 (or 32027630335 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 256221042664 in words is "two hundred fifty-six billion, two hundred twenty-one million, forty-two thousand, six hundred sixty-four".