257664 has 64 divisors (see below), whose sum is σ = 758880. Its totient is φ = 76800.

The previous prime is 257657. The next prime is 257671. The reversal of 257664 is 466752.

257664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (257657) and next prime (257671).

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

257664 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4194 + ... + 4254.

2²⁵⁷⁶⁶⁴ is an apocalyptic number.

257664 is a gapful number since it is divisible by the number (24) 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 257664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (379440).

257664 is an abundant number, since it is smaller than the sum of its proper divisors (501216).

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

257664 is a wasteful number, since it uses less digits than its factorization.

257664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89 (or 77 counting only the distinct ones).

The product of its digits is 10080, while the sum is 30.

The square root of 257664 is about 507.6061465349. The cubic root of 257664 is about 63.6333198297.

The spelling of 257664 in words is "two hundred fifty-seven thousand, six hundred sixty-four".