256509165505536 has 880 divisors, whose sum is σ = 804931231104000. Its totient is φ = 81259573248000.

The previous prime is 256509165505507. The next prime is 256509165505543. The reversal of 256509165505536 is 635505561905652.

256509165505536 is a `hidden beast` number, since 2 + 5 + 6 + 5 + 0 + 91 + 6 + 5 + 5 + 0 + 5 + 536 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 171120189715 + ... + 171120191213.

It is an arithmetic number, because the mean of its divisors is an integer number (914694580800).

Almost surely, 2^{256509165505536} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256509165505536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (402465615552000).

256509165505536 is an abundant number, since it is smaller than the sum of its proper divisors (548422065598464).

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

256509165505536 is a wasteful number, since it uses less digits than its factorization.

256509165505536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2714 (or 2687 counting only the distinct ones).

The product of its (nonzero) digits is 182250000, while the sum is 63.

The spelling of 256509165505536 in words is "two hundred fifty-six trillion, five hundred nine billion, one hundred sixty-five million, five hundred five thousand, five hundred thirty-six".