257439728 has 180 divisors, whose sum is σ = 659656440. Its totient is φ = 96864768.

The previous prime is 257439701. The next prime is 257439731. The reversal of 257439728 is 827934752.

It is a happy number.

Its product of digits (846720) is a multiple of the sum of its prime factors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 3842351 + ... + 3842417.

It is an arithmetic number, because the mean of its divisors is an integer number (3664758).

Almost surely, 2^257439728 is an apocalyptic number.

257439728 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 257439728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (329828220).

257439728 is an abundant number, since it is smaller than the sum of its proper divisors (402216712).

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

257439728 is a wasteful number, since it uses less digits than its factorization.

257439728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 118 counting only the distinct ones).

The product of its digits is 846720, while the sum is 47.

The square root of 257439728 is about 16044.9284199089. The cubic root of 257439728 is about 636.1485222008.

The spelling of 257439728 in words is "two hundred fifty-seven million, four hundred thirty-nine thousand, seven hundred twenty-eight".