251749918368 has 72 divisors (see below), whose sum is σ = 770984136468. Its totient is φ = 77461512192.

The previous prime is 251749918363. The next prime is 251749918369. The reversal of 251749918368 is 863819947152.

251749918368 is a `hidden beast` number, since 2 + 5 + 1 + 7 + 499 + 1 + 83 + 68 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 214009862544 + 37740055824 = 462612^2 + 194268^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Smith number, since the sum of its digits (63) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (251749918363) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33616705 + ... + 33624192.

Almost surely, 2^251749918368 is an apocalyptic number.

It is an amenable number.

251749918368 is an abundant number, since it is smaller than the sum of its proper divisors (519234218100).

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

251749918368 is a wasteful number, since it uses less digits than its factorization.

251749918368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67240926 (or 67240915 counting only the distinct ones).

The product of its digits is 26127360, while the sum is 63.

The spelling of 251749918368 in words is "two hundred fifty-one billion, seven hundred forty-nine million, nine hundred eighteen thousand, three hundred sixty-eight".