256717818280 has 256 divisors, whose sum is σ = 774182707200. Its totient is φ = 74190919680.

The previous prime is 256717818197. The next prime is 256717818289. The reversal of 256717818280 is 82818717652.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is not an unprimeable number, because it can be changed into a prime (256717818289) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2703772 + ... + 2797108.

It is an arithmetic number, because the mean of its divisors is an integer number (3024151200).

Almost surely, 2^256717818280 is an apocalyptic number.

256717818280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256717818280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (387091353600).

256717818280 is an abundant number, since it is smaller than the sum of its proper divisors (517464888920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256717818280 is a wasteful number, since it uses less digits than its factorization.

256717818280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93432 (or 93428 counting only the distinct ones).

The product of its (nonzero) digits is 3010560, while the sum is 55.

The spelling of 256717818280 in words is "two hundred fifty-six billion, seven hundred seventeen million, eight hundred eighteen thousand, two hundred eighty".