6691323991 has 8 divisors (see below), whose sum is σ = 7535098368. Its totient is φ = 5886795000.

The previous prime is 6691323959. The next prime is 6691324001. The reversal of 6691323991 is 1993231966.

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 6691323991 - 2⁵ = 6691323959 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 (6691323931) 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, 9810985 + ... + 9811666.

It is an arithmetic number, because the mean of its divisors is an integer number (941887296).

Almost surely, 2^6691323991 is an apocalyptic number.

6691323991 is a deficient number, since it is larger than the sum of its proper divisors (843774377).

6691323991 is a wasteful number, since it uses less digits than its factorization.

6691323991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19622693.

The product of its digits is 472392, while the sum is 49.

The square root of 6691323991 is about 81800.5133908095. The cubic root of 6691323991 is about 1884.3895460104.

The spelling of 6691323991 in words is "six billion, six hundred ninety-one million, three hundred twenty-three thousand, nine hundred ninety-one".