256403165645 has 16 divisors (see below), whose sum is σ = 353321110080. Its totient is φ = 176660553600.

The previous prime is 256403165639. The next prime is 256403165651. The reversal of 256403165645 is 546561304652.

It is an interprime number because it is at equal distance from previous prime (256403165639) and next prime (256403165651).

It is a de Polignac number, because none of the positive numbers 2^k-256403165645 is a prime.

It is a super-3 number, since 3×256403165645³ (a number of 35 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 256403165645.

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, 122679896 + ... + 122681985.

It is an arithmetic number, because the mean of its divisors is an integer number (22082569380).

Almost surely, 2^256403165645 is an apocalyptic number.

It is an amenable number.

256403165645 is a deficient number, since it is larger than the sum of its proper divisors (96917944435).

256403165645 is a wasteful number, since it uses less digits than its factorization.

256403165645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245361916.

The product of its (nonzero) digits is 2592000, while the sum is 47.

The spelling of 256403165645 in words is "two hundred fifty-six billion, four hundred three million, one hundred sixty-five thousand, six hundred forty-five".