251555840928 has 216 divisors, whose sum is σ = 832630518720. Its totient is φ = 71832096000.

The previous prime is 251555840917. The next prime is 251555840933. The reversal of 251555840928 is 829048555152.

251555840928 is a `hidden beast` number, since 2 + 5 + 1 + 55 + 584 + 0 + 9 + 2 + 8 = 666.

It is a super-2 number, since 2×251555840928² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 31762153 + ... + 31770071.

It is an arithmetic number, because the mean of its divisors is an integer number (3854770920).

Almost surely, 2^251555840928 is an apocalyptic number.

251555840928 is a gapful number since it is divisible by the number (28) 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 251555840928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (416315259360).

251555840928 is an abundant number, since it is smaller than the sum of its proper divisors (581074677792).

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

251555840928 is a wasteful number, since it uses less digits than its factorization.

251555840928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10200 (or 10182 counting only the distinct ones).

The product of its (nonzero) digits is 5760000, while the sum is 54.

The spelling of 251555840928 in words is "two hundred fifty-one billion, five hundred fifty-five million, eight hundred forty thousand, nine hundred twenty-eight".