251555328 has 160 divisors (see below), whose sum is σ = 769950720. Its totient is φ = 81008640.

The previous prime is 251555263. The next prime is 251555329. The reversal of 251555328 is 823555152.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 251555292 and 251555301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251555329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 428251 + ... + 428837.

It is an arithmetic number, because the mean of its divisors is an integer number (4812192).

Almost surely, 2^251555328 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 251555328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (384975360).

251555328 is an abundant number, since it is smaller than the sum of its proper divisors (518395392).

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

251555328 is an equidigital number, since it uses as much as digits as its factorization.

251555328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645 (or 623 counting only the distinct ones).

The product of its digits is 60000, while the sum is 36.

The square root of 251555328 is about 15860.4958308371. The cubic root of 251555328 is about 631.2642187694.

The spelling of 251555328 in words is "two hundred fifty-one million, five hundred fifty-five thousand, three hundred twenty-eight".