257320647 has 6 divisors (see below), whose sum is σ = 371685392. Its totient is φ = 171547092.

The previous prime is 257320639. The next prime is 257320649. The reversal of 257320647 is 746023752.

It is a happy number.

257320647 is a `hidden beast` number, since 2 + 5 + 7 + 3 + 2 + 0 + 647 = 666.

It is not a de Polignac number, because 257320647 - 2³ = 257320639 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257320649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14295583 + ... + 14295600.

Almost surely, 2^257320647 is an apocalyptic number.

257320647 is a deficient number, since it is larger than the sum of its proper divisors (114364745).

257320647 is a wasteful number, since it uses less digits than its factorization.

257320647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28591189 (or 28591186 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 36.

The square root of 257320647 is about 16041.2171296320. The cubic root of 257320647 is about 636.0504217175.

It can be divided in two parts, 2573 and 20647, that added together give a triangular number (23220 = T₂₁₅).

The spelling of 257320647 in words is "two hundred fifty-seven million, three hundred twenty thousand, six hundred forty-seven".