256663021535 has 16 divisors (see below), whose sum is σ = 311072804352. Its totient is φ = 203279328000.

The previous prime is 256663021513. The next prime is 256663021543. The reversal of 256663021535 is 535120366652.

It is not a de Polignac number, because 256663021535 - 2¹² = 256663017439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10350722 + ... + 10375488.

It is an arithmetic number, because the mean of its divisors is an integer number (19442050272).

Almost surely, 2^256663021535 is an apocalyptic number.

256663021535 is a deficient number, since it is larger than the sum of its proper divisors (54409782817).

256663021535 is a wasteful number, since it uses less digits than its factorization.

256663021535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45394.

The product of its (nonzero) digits is 972000, while the sum is 44.

The spelling of 256663021535 in words is "two hundred fifty-six billion, six hundred sixty-three million, twenty-one thousand, five hundred thirty-five".