257235640 has 64 divisors (see below), whose sum is σ = 598752000. Its totient is φ = 99394560.

The previous prime is 257235617. The next prime is 257235647. The reversal of 257235640 is 46532752.

It is a junction number, because it is equal to n+sod(n) for n = 257235596 and 257235605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257235647) 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, 178041 + ... + 179479.

It is an arithmetic number, because the mean of its divisors is an integer number (9355500).

Almost surely, 2^257235640 is an apocalyptic number.

257235640 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 257235640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (299376000).

257235640 is an abundant number, since it is smaller than the sum of its proper divisors (341516360).

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

257235640 is a wasteful number, since it uses less digits than its factorization.

257235640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1600 (or 1596 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 34.

The square root of 257235640 is about 16038.5672676832. The cubic root of 257235640 is about 635.9803733247.

The spelling of 257235640 in words is "two hundred fifty-seven million, two hundred thirty-five thousand, six hundred forty".