256661088835401 has 40 divisors (see below), whose sum is σ = 392774288631648. Its totient is φ = 166927417272000.

The previous prime is 256661088835391. The next prime is 256661088835433. The reversal of 256661088835401 is 104538880166652.

It is not a de Polignac number, because 256661088835401 - 2¹⁵ = 256661088802633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (256661088835441) 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 39 ways as a sum of consecutive naturals, for example, 82869246 + ... + 85910616.

Almost surely, 2^{256661088835401} is an apocalyptic number.

It is an amenable number.

256661088835401 is a deficient number, since it is larger than the sum of its proper divisors (136113199796247).

256661088835401 is a wasteful number, since it uses less digits than its factorization.

256661088835401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3066835 (or 3066826 counting only the distinct ones).

The product of its (nonzero) digits is 66355200, while the sum is 63.

The spelling of 256661088835401 in words is "two hundred fifty-six trillion, six hundred sixty-one billion, eighty-eight million, eight hundred thirty-five thousand, four hundred one".