251861564934 has 48 divisors (see below), whose sum is σ = 626453947392. Its totient is φ = 71637746544.

The previous prime is 251861564887. The next prime is 251861564987. The reversal of 251861564934 is 439465168152.

251861564934 is a `hidden beast` number, since 2 + 5 + 18 + 61 + 564 + 9 + 3 + 4 = 666.

251861564934 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4453744 + ... + 4509939.

It is an arithmetic number, because the mean of its divisors is an integer number (13051123904).

Almost surely, 2^251861564934 is an apocalyptic number.

251861564934 is an abundant number, since it is smaller than the sum of its proper divisors (374592382458).

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

251861564934 is a wasteful number, since it uses less digits than its factorization.

251861564934 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8963921 (or 8963918 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 54.

The spelling of 251861564934 in words is "two hundred fifty-one billion, eight hundred sixty-one million, five hundred sixty-four thousand, nine hundred thirty-four".