668578693 has 4 divisors (see below), whose sum is σ = 674827200. Its totient is φ = 662330188.

The previous prime is 668578667. The next prime is 668578699. The reversal of 668578693 is 396875866.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 396875866 = 2 ⋅198437933.

It is a cyclic number.

It is not a de Polignac number, because 668578693 - 2⁹ = 668578181 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 (668578699) 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 in 3 ways as a sum of consecutive naturals, for example, 3124093 + ... + 3124306.

It is an arithmetic number, because the mean of its divisors is an integer number (168706800).

Almost surely, 2^668578693 is an apocalyptic number.

It is an amenable number.

668578693 is a deficient number, since it is larger than the sum of its proper divisors (6248507).

668578693 is a wasteful number, since it uses less digits than its factorization.

668578693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6248506.

The product of its digits is 13063680, while the sum is 58.

The square root of 668578693 is about 25856.8886952781. Note that the first 3 decimals coincide. The cubic root of 668578693 is about 874.4148220138.

The spelling of 668578693 in words is "six hundred sixty-eight million, five hundred seventy-eight thousand, six hundred ninety-three".