257821280 has 48 divisors (see below), whose sum is σ = 612813600. Its totient is φ = 102500352.

The previous prime is 257821261. The next prime is 257821301. The reversal of 257821280 is 82128752.

It is a self number, because there is not a number n which added to its sum of digits gives 257821280.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21896 + ... + 31544.

It is an arithmetic number, because the mean of its divisors is an integer number (12766950).

Almost surely, 2^257821280 is an apocalyptic number.

257821280 is a gapful number since it is divisible by the number (20) 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 257821280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (306406800).

257821280 is an abundant number, since it is smaller than the sum of its proper divisors (354992320).

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

257821280 is a wasteful number, since it uses less digits than its factorization.

257821280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9831 (or 9823 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 257821280 is about 16056.8141298329. The cubic root of 257821280 is about 636.4626461159.

The spelling of 257821280 in words is "two hundred fifty-seven million, eight hundred twenty-one thousand, two hundred eighty".