257720545 has 4 divisors (see below), whose sum is σ = 309264660. Its totient is φ = 206176432.

The previous prime is 257720539. The next prime is 257720549. The reversal of 257720545 is 545027752.

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 38887696 + 218832849 = 6236^2 + 14793^2 .

It is a cyclic number.

It is not a de Polignac number, because 257720545 - 2⁵ = 257720513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (257720549) 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, 25772050 + ... + 25772059.

It is an arithmetic number, because the mean of its divisors is an integer number (77316165).

Almost surely, 2^257720545 is an apocalyptic number.

It is an amenable number.

257720545 is a deficient number, since it is larger than the sum of its proper divisors (51544115).

257720545 is an equidigital number, since it uses as much as digits as its factorization.

257720545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51544114.

The product of its (nonzero) digits is 98000, while the sum is 37.

The square root of 257720545 is about 16053.6769931377. The cubic root of 257720545 is about 636.3797431885.

The spelling of 257720545 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred forty-five".