256205721600 has 1560 divisors, whose sum is σ = 1061836680960. Its totient is φ = 60728279040.

The previous prime is 256205721571. The next prime is 256205721659. The reversal of 256205721600 is 6127502652.

256205721600 is a `hidden beast` number, since 2 + 5 + 6 + 20 + 5 + 7 + 21 + 600 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 3243110361 + ... + 3243110439.

Almost surely, 2^256205721600 is an apocalyptic number.

256205721600 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 256205721600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (530918340480).

256205721600 is an abundant number, since it is smaller than the sum of its proper divisors (805630959360).

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

256205721600 is a wasteful number, since it uses less digits than its factorization.

256205721600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 36.

The spelling of 256205721600 in words is "two hundred fifty-six billion, two hundred five million, seven hundred twenty-one thousand, six hundred".