257720017 has 8 divisors (see below), whose sum is σ = 273026376. Its totient is φ = 242429952.

The previous prime is 257720011. The next prime is 257720069. The reversal of 257720017 is 710027752.

It can be written as a sum of positive squares in 4 ways, for example, as 85821696 + 171898321 = 9264^2 + 13111^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 257720017 - 2¹¹ = 257717969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257720011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46633 + ... + 51865.

It is an arithmetic number, because the mean of its divisors is an integer number (34128297).

Almost surely, 2^257720017 is an apocalyptic number.

It is an amenable number.

257720017 is a deficient number, since it is larger than the sum of its proper divisors (15306359).

257720017 is a wasteful number, since it uses less digits than its factorization.

257720017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8147.

The product of its (nonzero) digits is 6860, while the sum is 31.

The square root of 257720017 is about 16053.6605482986. The cubic root of 257720017 is about 636.3793085979.

Adding to 257720017 its reverse (710027752), we get a palindrome (967747769).

The spelling of 257720017 in words is "two hundred fifty-seven million, seven hundred twenty thousand, seventeen".