666191938939 has 8 divisors (see below), whose sum is σ = 668687374080. Its totient is φ = 663700949736.

The previous prime is 666191938873. The next prime is 666191938969. The reversal of 666191938939 is 939839191666.

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 666191938939 - 2²¹ = 666189841787 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666191938969) 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 7 ways as a sum of consecutive naturals, for example, 811087 + ... + 1410760.

It is an arithmetic number, because the mean of its divisors is an integer number (83585921760).

Almost surely, 2^666191938939 is an apocalyptic number.

666191938939 is a deficient number, since it is larger than the sum of its proper divisors (2495435141).

666191938939 is a wasteful number, since it uses less digits than its factorization.

666191938939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2222969.

The product of its digits is 102036672, while the sum is 70.

The spelling of 666191938939 in words is "six hundred sixty-six billion, one hundred ninety-one million, nine hundred thirty-eight thousand, nine hundred thirty-nine".