256601851920 has 120 divisors (see below), whose sum is σ = 867538503000. Its totient is φ = 67967889408.

The previous prime is 256601851879. The next prime is 256601851939. The reversal of 256601851920 is 29158106652.

256601851920 is a `hidden beast` number, since 2 + 5 + 6 + 601 + 8 + 5 + 19 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 112275216 + 256489576704 = 10596^2 + 506448^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1088665 + ... + 1303224.

It is an arithmetic number, because the mean of its divisors is an integer number (7229487525).

Almost surely, 2^256601851920 is an apocalyptic number.

256601851920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

256601851920 is an abundant number, since it is smaller than the sum of its proper divisors (610936651080).

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

256601851920 is a wasteful number, since it uses less digits than its factorization.

256601851920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2392057 (or 2392048 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 256601851920 in words is "two hundred fifty-six billion, six hundred one million, eight hundred fifty-one thousand, nine hundred twenty".