256187888640 has 440 divisors, whose sum is σ = 947694054912. Its totient is φ = 66109685760.

The previous prime is 256187888623. The next prime is 256187888657. The reversal of 256187888640 is 46888781652.

256187888640 is a `hidden beast` number, since 2 + 5 + 618 + 7 + 8 + 8 + 8 + 6 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (256187888623) and next prime (256187888657).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 12846357 + ... + 12866283.

Almost surely, 2^256187888640 is an apocalyptic number.

256187888640 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 256187888640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (473847027456).

256187888640 is an abundant number, since it is smaller than the sum of its proper divisors (691506166272).

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

256187888640 is a wasteful number, since it uses less digits than its factorization.

256187888640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19995 (or 19968 counting only the distinct ones).

The product of its (nonzero) digits is 41287680, while the sum is 63.

The spelling of 256187888640 in words is "two hundred fifty-six billion, one hundred eighty-seven million, eight hundred eighty-eight thousand, six hundred forty".