256021440641 has 8 divisors (see below), whose sum is σ = 258082382400. Its totient is φ = 253965945168.

The previous prime is 256021440611. The next prime is 256021440671. The reversal of 256021440641 is 146044120652.

It is an interprime number because it is at equal distance from previous prime (256021440611) and next prime (256021440671).

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256021440641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256021440611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1267151 + ... + 1455236.

It is an arithmetic number, because the mean of its divisors is an integer number (32260297800).

Almost surely, 2^256021440641 is an apocalyptic number.

It is an amenable number.

256021440641 is a deficient number, since it is larger than the sum of its proper divisors (2060941759).

256021440641 is a wasteful number, since it uses less digits than its factorization.

256021440641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2723143.

The product of its (nonzero) digits is 46080, while the sum is 35.

The spelling of 256021440641 in words is "two hundred fifty-six billion, twenty-one million, four hundred forty thousand, six hundred forty-one".