257720530 has 8 divisors (see below), whose sum is σ = 463896972. Its totient is φ = 103088208.

The previous prime is 257720513. The next prime is 257720531. The reversal of 257720530 is 35027752.

It can be written as a sum of positive squares in 2 ways, for example, as 242518329 + 15202201 = 15573^2 + 3899^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 257720492 and 257720501.

It is not an unprimeable number, because it can be changed into a prime (257720531) 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 3 ways as a sum of consecutive naturals, for example, 12886017 + ... + 12886036.

Almost surely, 2^257720530 is an apocalyptic number.

257720530 is a deficient number, since it is larger than the sum of its proper divisors (206176442).

257720530 is a wasteful number, since it uses less digits than its factorization.

257720530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25772060.

The product of its (nonzero) digits is 14700, while the sum is 31.

The square root of 257720530 is about 16053.6765259550. The cubic root of 257720530 is about 636.3797308422.

The spelling of 257720530 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred thirty".