257768993 has 4 divisors (see below), whose sum is σ = 258024468. Its totient is φ = 257513520.

The previous prime is 257768989. The next prime is 257769013. The reversal of 257768993 is 399867752.

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 4545424 + 253223569 = 2132^2 + 15913^2 .

It is a cyclic number.

It is not a de Polignac number, because 257768993 - 2² = 257768989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257768983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126218 + ... + 128243.

It is an arithmetic number, because the mean of its divisors is an integer number (64506117).

Almost surely, 2^257768993 is an apocalyptic number.

It is an amenable number.

257768993 is a deficient number, since it is larger than the sum of its proper divisors (255475).

257768993 is a wasteful number, since it uses less digits than its factorization.

257768993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255474.

The product of its digits is 5715360, while the sum is 56.

The square root of 257768993 is about 16055.1858600267. The cubic root of 257768993 is about 636.4196176373.

The spelling of 257768993 in words is "two hundred fifty-seven million, seven hundred sixty-eight thousand, nine hundred ninety-three".