256641437051217 has 12 divisors (see below), whose sum is σ = 379325328148624. Its totient is φ = 167115354358680.

The previous prime is 256641437051143. The next prime is 256641437051257. The reversal of 256641437051217 is 712150734146652.

256641437051217 is a `hidden beast` number, since 2 + 5 + 6 + 6 + 4 + 1 + 4 + 370 + 51 + 217 = 666.

It is not a de Polignac number, because 256641437051217 - 2¹⁹ = 256641436526929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256641437051257) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 331578083659 + ... + 331578084432.

Almost surely, 2^{256641437051217} is an apocalyptic number.

It is an amenable number.

256641437051217 is a deficient number, since it is larger than the sum of its proper divisors (122683891097407).

256641437051217 is a wasteful number, since it uses less digits than its factorization.

256641437051217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663156168140 (or 663156168137 counting only the distinct ones).

The product of its (nonzero) digits is 8467200, while the sum is 54.

The spelling of 256641437051217 in words is "two hundred fifty-six trillion, six hundred forty-one billion, four hundred thirty-seven million, fifty-one thousand, two hundred seventeen".