251978364 has 72 divisors (see below), whose sum is σ = 720615168. Its totient is φ = 76353840.

The previous prime is 251978347. The next prime is 251978383. The reversal of 251978364 is 463879152.

251978364 is a `hidden beast` number, since 2 + 519 + 78 + 3 + 64 = 666.

251978364 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 polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1092 + ... + 22475.

It is an arithmetic number, because the mean of its divisors is an integer number (10008544).

Almost surely, 2^251978364 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251978364, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (360307584).

251978364 is an abundant number, since it is smaller than the sum of its proper divisors (468636804).

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

251978364 is a wasteful number, since it uses less digits than its factorization.

251978364 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23597 (or 23583 counting only the distinct ones).

The product of its digits is 362880, while the sum is 45.

The square root of 251978364 is about 15873.8263818148. The cubic root of 251978364 is about 631.6178824287.

The spelling of 251978364 in words is "two hundred fifty-one million, nine hundred seventy-eight thousand, three hundred sixty-four".