666139393 has 8 divisors (see below), whose sum is σ = 676529280. Its totient is φ = 655762800.

The previous prime is 666139391. The next prime is 666139399. The reversal of 666139393 is 393931666.

666139393 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 666139393 - 2¹ = 666139391 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666139391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 155403 + ... + 159631.

It is an arithmetic number, because the mean of its divisors is an integer number (84566160).

Almost surely, 2^666139393 is an apocalyptic number.

It is an amenable number.

666139393 is a deficient number, since it is larger than the sum of its proper divisors (10389887).

666139393 is a wasteful number, since it uses less digits than its factorization.

666139393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6647.

The product of its digits is 472392, while the sum is 46.

The square root of 666139393 is about 25809.6763443481. The cubic root of 666139393 is about 873.3500960046.

The spelling of 666139393 in words is "six hundred sixty-six million, one hundred thirty-nine thousand, three hundred ninety-three".