257897640 has 512 divisors, whose sum is σ = 1103155200. Its totient is φ = 46448640.

The previous prime is 257897639. The next prime is 257897641. The reversal of 257897640 is 46798752.

It is an interprime number because it is at equal distance from previous prime (257897639) and next prime (257897641).

It is a super-2 number, since 2×257897640² = 133022385435139200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 257897640.

It is not an unprimeable number, because it can be changed into a prime (257897641) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2282224 + ... + 2282336.

It is an arithmetic number, because the mean of its divisors is an integer number (2154600).

Almost surely, 2^257897640 is an apocalyptic number.

257897640 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 257897640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (551577600).

257897640 is an abundant number, since it is smaller than the sum of its proper divisors (845257560).

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

257897640 is a wasteful number, since it uses less digits than its factorization.

257897640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177 (or 173 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 48.

The square root of 257897640 is about 16059.1917604841. The cubic root of 257897640 is about 636.5254745093.

The spelling of 257897640 in words is "two hundred fifty-seven million, eight hundred ninety-seven thousand, six hundred forty".