257664393 has 36 divisors (see below), whose sum is σ = 458427060. Its totient is φ = 138571776.

The previous prime is 257664383. The next prime is 257664397. The reversal of 257664393 is 393466752.

257664393 is a `hidden beast` number, since 257 + 6 + 6 + 4 + 393 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 233722944 + 23941449 = 15288^2 + 4893^2 .

It is not a de Polignac number, because 257664393 - 2⁹ = 257663881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (257664397) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9688 + ... + 24681.

It is an arithmetic number, because the mean of its divisors is an integer number (12734085).

Almost surely, 2^257664393 is an apocalyptic number.

It is an amenable number.

257664393 is a deficient number, since it is larger than the sum of its proper divisors (200762667).

257664393 is a wasteful number, since it uses less digits than its factorization.

257664393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34406 (or 34396 counting only the distinct ones).

The product of its digits is 816480, while the sum is 45.

The square root of 257664393 is about 16051.9280150392. The cubic root of 257664393 is about 636.3335218173. Note that the first 3 decimals are identical.

The spelling of 257664393 in words is "two hundred fifty-seven million, six hundred sixty-four thousand, three hundred ninety-three".