257720018 has 4 divisors (see below), whose sum is σ = 386580030. Its totient is φ = 128860008.

The previous prime is 257720011. The next prime is 257720069. The reversal of 257720018 is 810027752.

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

It can be written as a sum of positive squares in only one way, i.e., 255264529 + 2455489 = 15977^2 + 1567^2 .

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 as a sum of consecutive naturals, namely, 64430003 + ... + 64430006.

Almost surely, 2^257720018 is an apocalyptic number.

257720018 is a deficient number, since it is larger than the sum of its proper divisors (128860012).

257720018 is a wasteful number, since it uses less digits than its factorization.

257720018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128860011.

The product of its (nonzero) digits is 7840, while the sum is 32.

The square root of 257720018 is about 16053.6605794442. The cubic root of 257720018 is about 636.3793094210.

The spelling of 257720018 in words is "two hundred fifty-seven million, seven hundred twenty thousand, eighteen".