257720605 has 4 divisors (see below), whose sum is σ = 309264732. Its totient is φ = 206176480.

The previous prime is 257720563. The next prime is 257720621. The reversal of 257720605 is 506027752.

It is a happy number.

257720605 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 46977316 + 210743289 = 6854^2 + 14517^2 .

It is not a de Polignac number, because 257720605 - 2¹¹ = 257718557 is a prime.

It is a super-3 number, since 3×257720605³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25772056 + ... + 25772065.

It is an arithmetic number, because the mean of its divisors is an integer number (77316183).

Almost surely, 2^257720605 is an apocalyptic number.

It is an amenable number.

257720605 is a deficient number, since it is larger than the sum of its proper divisors (51544127).

257720605 is an equidigital number, since it uses as much as digits as its factorization.

257720605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51544126.

The product of its (nonzero) digits is 29400, while the sum is 34.

The square root of 257720605 is about 16053.6788618684. The cubic root of 257720605 is about 636.3797925737.

The spelling of 257720605 in words is "two hundred fifty-seven million, seven hundred twenty thousand, six hundred five".