257643242 has 4 divisors (see below), whose sum is σ = 386464866. Its totient is φ = 128821620.

The previous prime is 257643241. The next prime is 257643259. The reversal of 257643242 is 242346752.

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., 244891201 + 12752041 = 15649^2 + 3571^2 .

It is not an unprimeable number, because it can be changed into a prime (257643241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64410809 + ... + 64410812.

Almost surely, 2^257643242 is an apocalyptic number.

257643242 is a deficient number, since it is larger than the sum of its proper divisors (128821624).

257643242 is a wasteful number, since it uses less digits than its factorization.

257643242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128821623.

The product of its digits is 80640, while the sum is 35.

The square root of 257643242 is about 16051.2691710033. The cubic root of 257643242 is about 636.3161096862.

Adding to 257643242 its reverse (242346752), we get a palindrome (499989994).

The spelling of 257643242 in words is "two hundred fifty-seven million, six hundred forty-three thousand, two hundred forty-two".