257065809 has 64 divisors (see below), whose sum is σ = 469862400. Its totient is φ = 123197760.

The previous prime is 257065807. The next prime is 257065819. The reversal of 257065809 is 908560752.

It is not a de Polignac number, because 257065809 - 2¹ = 257065807 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257065807) by changing a digit.

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 63 ways as a sum of consecutive naturals, for example, 146274 + ... + 148020.

It is an arithmetic number, because the mean of its divisors is an integer number (7341600).

Almost surely, 2^257065809 is an apocalyptic number.

It is an amenable number.

257065809 is a deficient number, since it is larger than the sum of its proper divisors (212796591).

257065809 is a wasteful number, since it uses less digits than its factorization.

257065809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1795 (or 1781 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 42.

The square root of 257065809 is about 16033.2719368194. The cubic root of 257065809 is about 635.8403811094.

The spelling of 257065809 in words is "two hundred fifty-seven million, sixty-five thousand, eight hundred nine".