256640637040260 has 192 divisors, whose sum is σ = 789079962746880. Its totient is φ = 61807595281920.

The previous prime is 256640637040201. The next prime is 256640637040273. The reversal of 256640637040260 is 62040736046652.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 68679054 + ... + 72319386.

It is an arithmetic number, because the mean of its divisors is an integer number (4109791472640).

Almost surely, 2^{256640637040260} is an apocalyptic number.

256640637040260 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 256640637040260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (394539981373440).

256640637040260 is an abundant number, since it is smaller than the sum of its proper divisors (532439325706620).

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

256640637040260 is a wasteful number, since it uses less digits than its factorization.

256640637040260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3641058 (or 3641056 counting only the distinct ones).

The product of its (nonzero) digits is 8709120, while the sum is 51.

The spelling of 256640637040260 in words is "two hundred fifty-six trillion, six hundred forty billion, six hundred thirty-seven million, forty thousand, two hundred sixty".