668593493 has 4 divisors (see below), whose sum is σ = 707922540. Its totient is φ = 629264448.

The previous prime is 668593483. The next prime is 668593507. The reversal of 668593493 is 394395866.

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 622652209 + 45941284 = 24953^2 + 6778^2 .

It is a cyclic number.

It is not a de Polignac number, because 668593493 - 2²² = 664399189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668593403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19664498 + ... + 19664531.

It is an arithmetic number, because the mean of its divisors is an integer number (176980635).

Almost surely, 2^668593493 is an apocalyptic number.

It is an amenable number.

668593493 is a deficient number, since it is larger than the sum of its proper divisors (39329047).

668593493 is a wasteful number, since it uses less digits than its factorization.

668593493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39329046.

The product of its digits is 4199040, while the sum is 53.

The square root of 668593493 is about 25857.1748843527. The cubic root of 668593493 is about 874.4212741308.

The spelling of 668593493 in words is "six hundred sixty-eight million, five hundred ninety-three thousand, four hundred ninety-three".